Skip Navigation


Human Molecular Genetics Advance Access originally published online on June 1, 2005
Human Molecular Genetics 2005 14(14):1991-2002; doi:10.1093/hmg/ddi204
This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
14/14/1991    most recent
ddi204v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (59)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Conley, Y. P.
Right arrow Articles by Gorin, M. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Conley, Y. P.
Right arrow Articles by Gorin, M. B.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2005. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oupjournals.org

Candidate gene analysis suggests a role for fatty acid biosynthesis and regulation of the complement system in the etiology of age-related maculopathy

Yvette P. Conley1,2, Anbupalam Thalamuthu2, Johanna Jakobsdottir3, Daniel E. Weeks2,3, Tammy Mah4, Robert E. Ferrell2 and Michael B. Gorin2,4,*

1Department of Health Promotion and Development, School of Nursing, 2Department of Human Genetics, 3Department of Biostatistics, Graduate School of Public Health and 4Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA

* To whom correspondence should be addressed at: Departments of Ophthalmology and Human Genetics, School of Medicine and Graduate School of Public Health, The Eye and Ear Institute Building, 203 Lothrop Street, University of Pittsburgh, Pittsburgh, PA 15213, USA. Tel: +1 4126477726; Fax: +1 4126475880; Email: gorinmb{at}upmc.edu

Received March 11, 2005; Revised May 12, 2005; Accepted May 23, 2005


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
Age-related maculopathy (ARM) is a leading cause of visual impairment in elderly Americans and is a complex genetic disorder. Hypothesized pathways for the etiology of ARM include cholesterol and lipoprotein metabolism and transport, extracellular matrix integrity, oxidative stress and inflammatory/immunologic processes. This study investigates 21 polymorphisms within 15 candidate genes whose products function within these pathways by performing family and case–control genetic association studies using clearly affected familial cases (n=338 families, 796 individuals), clearly affected, unrelated sporadic cases (n=196) and clearly unaffected, unrelated controls (n=120). Two genes demonstrated significant association with ARM status. A Met299Val variant in the elongation of very long chain fatty acids-like 4 (ELOVL4) gene was significantly associated with ARM in the case–control allele (P=0.001), case–control genotype (P=0.001) and case–control family (P<0.0001) tests. A Tyr402His variant in exon 9 in the complement factor H (CFH) gene was also significantly associated with ARM in the case–control allele (P<0.0001), case–control genotype (P<0.0001) and case–control family (P<0.0001) tests. All of these results remain significant after adjusting for false discovery rates to control for the impact of multiple testing. In addition, the CFH variant appears to play a role in exudative and atrophic disease, whereas the ELOVL4 variant may play a greater role in exudative disease in our population. These results support a potential role for multiple pathways in the etiology of ARM, including pathways involved with fatty acid biosynthesis and the complement system.


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
Age-related maculopathy (ARM) is one of the leading causes of blindness of the elderly in the United States (1Go). Genetic susceptibility plays a role in ARM etiology with heritability estimates ~45% (2Go). Several studies have used a genome-wide linkage approach to detect regions of the genome, which potentially contain genes involved in the etiology of ARM. Several regions of the genome have been implicated in multiple studies and strengthen support for these regions. Linkage to the 1q31 region has been the most consistent with seven separate analyses, implicating this region in the etiology of ARM (3Go–9Go). The region 10q26 has also received considerable support (3Go,4Go,6Go–8Go,10Go,11Go). Several other regions of the genome have been implicated in different studies with less replication.

In addition, many studies have taken a candidate gene approach to the study of the genetic etiology of ARM, implicating the genes for hemicentin (FIBL-6), elongation of very long chain fatty acids-like 4 (ELOVL4), angiotensin 1 converting enzyme (ACE), apolipoprotein E (APOE), paraoxonase (PON1), manganese superoxide dismutase (SOD2), cystatin C (CST3), ATP-binding cassette transporter (ABCA4) and the complement factor H (CFH) in ARM etiology. The gene for hemicentin, also known as fibulin 6 (FIBL-6), located at 1q25–q31 has been implicated in one large ARM family (12Go). In addition, FIBL-6 has homology to the EGF-containing fibulin-like extracellular matrix protein 1 gene known to be mutated in diseases characterized by early-onset drusen including Doyne's honeycomb and malattia leventinese macular degeneration (13Go). Mutations in ELOVL4, located at 6q14, which result in the production of a truncated protein have been associated with autosomal dominant macular dystrophy (14Go–16Go). ACE, located at 17q23, contains a well-characterized variant known to influence expression of ACE and this variant has been implicated in diabetic retinopathy and was shown to have a protective effect for ARM in one study (17Go). APOE, located at 19q13, has been associated with ARM in several studies, with the E4 allele potentially having a protective role (18Go–20Go). PON1, located at 7q21 and SOD2, located at 6q25, have been implicated in the exudative form of ARM each in one study (21Go,22Go). CST3, located at 20p11, has been associated with disease in German ARM subjects in one study (23Go). ABCA4, located at 1p21, has been implicated in ARM (24Go); however, our group has not been able to replicate this finding in our familial samples (11Go). A Tyr402His polymorphism within exon 9 of the CFH gene, located at 1q31, has been implicated in ARM in four previous studies to date (25Go–28Go).

Several hypotheses exist concerning the etiology of ARM including the involvement of cholesterol and lipoprotein metabolism and transport, extracellular matrix integrity, oxidative stress and inflammatory/immunologic processes. Support for the involvement of cholesterol and lipoprotein metabolism and transport include the commonalities between atherosclerotic deposits and drusen deposits on the retina of some ARM patients (29Go) and the significant contribution of cholesterol to the composition of drusen and the potential link between serum cholesterol levels and ARM etiology (30Go). Additional support for the role of cholesterol and lipoprotein metabolism and transport in ARM stems from the overlap of retinal degeneration in diseases such as abetalipoproteinemia, angioid streaks and from the fact that the retina is capable of de novo synthesis, assembly and secretion of lipids (31Go). Support for the involvement of extracellular matrix integrity involves the age-related changes, which have been noted in the retinal pigment epithelium and Bruch's membrane of the macula in ARM patients with the earliest signs of ARM found at Bruch's membrane (32Go). The accumulation of abnormal extracellular matrix resulting in thickening of Bruch's membrane is a hallmark of advanced ARM (33Go), and it has been suggested that this thickening might be due to impaired degradation of the extracellular matrix at this site (34Go). Additional support for the involvement of the integrity of the extracellular matrix in ARM relates to the evidence implicating genes involved with the extracellular matrix in early onset forms of macular degeneration. Examples include the involvement of the EGF-containing fibulin-like extracellular matrix protein 1 (EFEMP1) in malattia leventinese and Doyne's honeycomb retinal dystrophy (13Go), the involvement of the tissue inhibitor of metalloproteinases-3 (TIMP3) gene in Sorsby's fundus dystrophy (35Go) and the cadherin-3 gene in juvenile macular degeneration (36Go,37Go). Oxidative damage has also been hypothesized to play a role in the etiology of ARM, and a role of oxidative damage has been supported by cellular studies and clinical trials. Clinical trials have supported the intake of antioxidants to slow the progression of ARM (38Go); therefore, supporting a possible role for oxidative damage in ARM. In addition, the composition of the retina makes it a prime target for oxidative damage given its high consumption of oxygen and exposure to light (39Go) as well as studies demonstrating that lipid peroxidation occurs in the retina with the greatest extent of lipid peroxidation occurring in the macula (40Go). It has been suggested that inflammatory and immune responses may play a role in ARM etiology. This has been supported by the observation that chronic inflammation of the retina is related to the neovascularization and exudation from these new vessels often observed in the early stages of ARM (41Go). Animal studies investigating retinal wound healing also support the influence of the immune response and the inflammation on the development of retinal degeneration (42Go).

Although there are additional models of pathogenesis of ARM, our group has initially taken the route of investigating candidate genes found predominantly within our linked regions of 1q31 and 17q25 (3Go,4Go,11Go) with functions that fit within the hypotheses described earlier. A brief description of selected candidates can be found in Table 1.


View this table:
[in this window]
[in a new window]
  		Table 1. Description of candidate genes investigated
 

   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 
Identification of previously unknown variants for FIBL-6, RGS16 and PRELP
  • RGS16: An A->G transition was identified in intron 3 of the RGS16 gene at nucleotide 2164 based on GenBank accession no. AF009356.
  • FIBL-6: A GATA tetranucleotide repeat polymorphism was identified within intron 58. The range of PCR generated fragment sizes was 154–218 bp.
  • PRELP: A C->A transversion was identified within the untranslated region of exon 3 of the PRELP gene at nucleotide 1561 based on GenBank accession no. NM002725.

Allele frequency estimation
Estimates of the allele frequencies (Table 2) identify four polymorphisms with relatively large frequency differences between cases and controls. The ELOVL4 polymorphism: Met299Val, the intronic CFH polymorphism: rs10922093, the exon 9 CFH polymorphism: Tyr402His and allele 97 of the VLDLR repeat polymorphism. Also, three of the ApoH polymorphisms (ApoH160, ApoH107 and ApoH335) are not very polymorphic at all, and so are not considered further.


View this table:
[in this window]
[in a new window]
  		Table 2. Allele frequencies for all variants. The ‘case–control’ column gives the difference between the allele frequency estimates in the cases and in the controls
 
Hardy–Weinberg equilibrium testing
In the controls, only one locus, ACE, is significantly out of Hardy–Weinberg equilibrium (HWE). In the cases, both ACE and FIBL-6 are significantly out of HWE with P<0.0001. There is also some evidence that LAMC1 and APOE are out of HWE in the cases (P-values 0.028 and 0.056, respectively).

Association testing
When the allele test is applied to the case–control sample, four loci (FIBL-6, CFH, ELOVL4 and VLDLR) generate significant results (Table 3). Allele-based logistic regression allowing for sex and age effects for the two-allele markers generates similar conclusions (data not shown). Under the genotype test, only two of these, CFH and ELOVL4, are significant. When the CLUMP test is applied to the three multi-allelic markers, FIBL-6 generates only moderately significant results (P-value close to 0.01). When we analyze the family and the case–control data simultaneously, using the case–control association analysis of pedigree data, CCREL (43Go), CFH and ELOVL4 are significant. Figure 1 shows the genotype distributions for the Met299Val polymorphism in ELOVL4 and the Tyr402His polymorphism in CFH for the case–control sample. Haplotype-based association testing for the two polymorphisms in the CFH gene (rs10922093 and Tyr402His) was significant (P<0.001), whereas that for the APOHin6, APOH154 and APOH266 variants was not significant (P=0.906; minimum haplotype-specific P=0.267).


View this table:
[in this window]
[in a new window]
  		Table 3. Results of association analyses
 


View larger version (18K):
[in this window]
[in a new window]
  		Figure 1. The genotype distribution for ELOVL4 and CFH (Try402His). Gray bars are controls and white bars are cases.

 
Results for the clinical subphenotypes, exudative and atrophic forms of the disease, are summarized in Table 4. We find that the Tyr402His variant in the CFH gene is involved in all forms of the disease (P<0.0001 in all tests). The Met299Val variant in the ELOVL4 gene is clearly involved in the exudative form of the disease (P<0.01 in all tests); however, two out of the three tests do not show significance for the atrophic form of the disease, but this could be due to low power from the low number of atrophic cases (exudative=130 and atrophic=57). Combined analysis of the family and case–control data does show that the Met299Val variant in ELOVL4 may be involved in the atrophic form of the disease (P<0.0001).


View this table:
[in this window]
[in a new window]
  		Table 4. Results of association analyses for sub-clinical types
 
Multiple testing
When we use a false discovery rate (FDR) (44Go,45Go) of 0.05 for the 54 association P-values (allele, genotype, CLUMP and CCREL tests) in Table 3, we obtain a P-value cutoff of 0.007. Using this cutoff, we obtain one or more significant association tests results for the rs10922093 and Tyr402His variants within the CFH gene, the Met299Val variant in the ELOVL4 gene and the repeat variant in the VLDLR gene. These are noted in Table 3.


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
MATERIALS AND METHODS
 REFERENCES
 
The complex genetics of ARM is apparent given the number of regions of the genome that have been implicated through linkage analyses, as well as the many candidate gene association studies that have been published. The fact that most of the genes known to be involved with early onset, single gene maculopathies are not strongly involved in ARM adds to the complexity of ARM genetics. Replication of linkage findings on chromosomes 1q31 and 10q26, however, offers encouragement that determining the genetic basis of susceptibility to ARM is feasible.

Most of the results presented in this paper are non-significant findings. With our sample size, the case–control allele test has power >80% at alpha=0.01 to detect an odds ratio greater than 1.90 when the allele frequency is 0.20 in the controls and an odds ratio greater than 2.84 when the control allele frequency is 0.05. In addition, the association tests utilized for this study rapidly lose power as allelic heterogeneity increases (46Go). Therefore, these non-significant findings should not be interpreted as necessarily excluding these genes from playing a role in ARM. Indeed, a much larger pooled study (20Go), of which our data was a part of, found that the E4 allele of APOE was protective against ARM; although we see the same trend here in terms of the E4 allele being more frequent in controls than that in cases, our smaller study does not have enough power to reach significance on its own for APOE.

ELOVL4 appears to be significantly associated with ARM status in the case–control simulated {chi}2 test (P=0.001 for allele test; P=0.001 for genotype test) as well as in the family and case–control tests (P<0.0001). Finding association across several types of analyses strengthens the potential relationship between ELOVL4 and ARM status. An OR of 0.45 (95% CI: 0.29–0.71) for ELOVL4 could potentially indicate that having a valine at residue 299 is protective. Exon 6 of the ELOVL4 gene was evaluated in the cases using dHPLC and the only variant that could be identified was the Met299Val variant. None of the other reported mutations in exon 6, including the 5 bp deletion reported by Zhang et al. (14Go) in several families with Stargardt-like and autosomal dominant maculopathies, was found in any of our cases. The only variant that was genotyped in both the cases and the controls was the Met299Val variant due to the reported low frequency of other non-synonymous variants in ELOVL4. This Met299Val variant represents an amino acid change from one that is hydrophilic to one that is hydrophobic, indicating that it could have functional consequences; however, it should be noted that the amino acid at position 299 in the ELOVL4 protein is not conserved across species. It is interesting to note that to date all of the mutations in ELOVL4 that have been implicated in earlier-onset maculopathy have been truncation mutations (14Go–16Go) and it is possible that this missense variant is responsible for the more common, ARM, which is represented by our subject population. In addition, one previous study did not find an association of the Met299Val variant in ELOVL4 with ARM using a case–control analyses (47Go). This discrepancy may be explained by our use of familial and sporadic samples and their use of only sporadic samples, it may be due to the over-representation of exudative cases in our study versus atrophic samples in their study or it may be due to differences in population substructure or number of subjects investigated. The issue of different proportions of end-stage disease between the two populations may be a valid concern given the results of the clinical subphenotype analyses (Table 4), which indicate that the ELOVL4 variant may play a greater role in exudative disease versus atrophic disease.

FIBL-6 and VLDLR appear to be significantly associated with ARM status in the case–control simulated {chi}2 analysis (allele test P=0.011 and P=0.007, respectively). FIBL-6 is within our linked region on 1q31. The FIBL-6 gene is ~7 cM from the CFH gene on chromosome 1 and for this reason we would not expect linkage disequilibrium to be present between these two loci. Although FIBL-6 is also significant for both the genotype test and the CLUMP test, none of these associations remained significant after adjusting for the FDR. VLDLR is only significant for the allele test, however, this association remained after adjusting for the FDR and may indicate that further investigations are warranted. Furthermore, in the absence of a strong linkage signal at 9p24 where the VLDLR gene resides, the collective evidence that VLDLR is involved in ARM is not compelling at this time.

Complement factor H (CFH), located within our linked region of 1q31, is significantly associated with ARM status in all of our tests of association for the Tyr402His variant (Table 3); this strong signal is consistent with the findings of others (25Go–28Go). In addition, our clinical subphenotype analyses indicate that the variants in the CFH gene most likely play a role in exudative and atrophic disease (Table 4). This finding supports a role for immune defense mechanisms in the etiology of ARM. Data provided by studying individuals with abnormalities in the complement system suggest that endothelial cells are not adequately protected during an inflammatory insult (48Go) and that this may lead to predisposition to thrombotic microangiopathy (49Go), which could help to explain the initial stages of ARM. The joint distribution of the Tyr402His variant for CFH and the Met299Val variant for ELOVL4 (Fig. 1) is independently distributed in cases (P=0.840) and in controls (P=0.832).

These data support a potential role for genes involved in multiple pathways for ARM susceptibility particularly those involving fatty acid biosynthesis and the complement system with some evidence for extracellular matrix integrity and lipid metabolism, contributing to the complex nature of ARM etiology.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
REFERENCES
 
Subjects and DNA extraction
To ensure homogeneity and to avoid population substructure, we restricted analyses to Caucasian subjects; this results in relatively little loss of information since the vast majority of our subjects are Caucasians. We also restricted our attention to Type A affecteds, which fall into our most stringent model for clinical classification. Individuals in this category were classified as ‘affected’ only if they were clearly affected with ARM based on the extensive/coalescent drusen, the pigmentary changes (including pigment epithelial detachments) and/or the presence of end-stage disease (geographic atrophy and/or choroidal neovascular membranes).

Subjects fall into three categories: familial (n=338 families, 796 individuals), sporadic, unrelated, Type A affecteds (n=196) and unaffected, unrelated controls (n=120). Sporadic affected subjects were 61% females with a median age of onset of 72 years and unaffected controls were 54% females with a median age of assessment of 75 years. Control individuals were required to have no macular pathology other than a small number (less than 15) small hard drusen in the macula and no evidence of significant extramacular drusen. Recruitment and clinical characterization of the familial samples have been previously described (3Go,4Go,11Go). Sporadic affecteds and control subjects were recruited from two sources. One source was the initial contacts made during our recruitment of ARM families and these included individuals who were not eligible for our initial family-based studies (because of lack of an affected family member who was willing to participate) and spouses of affected individuals. A second source of sporadic cases and controls have been from the vitreo-retinal practice of the University of Pittsburgh Medical Center Eye Center, family members and community members who became informed of our studies from public information lectures and acquaintances. Clinical information was obtained on sporadic cases and controls and affection status assigned in the same manner as those who participated in our familial cohorts. The informed consent process for all subjects was approved by the institutional review board of the University of Pittsburgh. Genomic DNA was extracted from leukocytes obtained from whole blood collected into EDTA vacutainers using a simple salting-out procedure (50Go).

Clinical subphenotypes of advanced ARM
The affected sporadic cases were subphenotyped with respect to the presence of choroidal neovascular membranes (exudative disease) (n=130) and RPE atrophy (geographic atrophy) (n=57). The presence of a choroidal neovascular membrane in either or both eyes was considered sufficient for the designation of ‘exudative’ disease, whether or not geographic atrophy was also identified. The definition of geographic atrophy includes individuals with and without choroidal neovascular membranes, but with the additional requirement that geographic atrophy had to be present in at least one eye that had no history or no evidence of a choroidal neovascular membrane. This stipulation is necessary because clinicians often refer to a patient as having RPE atrophy or there is photographic evidence of RPE atrophy after treatment or spontaneous resolution of a choroidal neovascular membrane. Clinical studies have shown a high concordance of geographic atrophy between the two eyes of affected individuals, thus it is reasonable to use the presence of geographic atrophy in one eye (with no evidence of a choroidal neovascular membrane) to meet the clinical definition for subphenotyping.

Criteria for selection of polymorphisms within the candidate genes
Polymorphisms were selected based on several criteria for prioritization. First, polymorphisms with a high heterozygosity score were chosen to increase the likelihood of obtaining informative data to detect an association with ARM even if the allele was not disease-causing, but in linkage disequilibrium with a true causative gene. Secondly, polymorphisms that result in a non-synonymous amino acid change were chosen and thirdly, polymorphisms that were likely to be informative and had allele frequency differences between Caucasians and African Americans were chosen.

New variant identification
Previously unknown informative variants for FIBL-6, RGS16 and PRELP were identified for this project. Primer sequences, PCR annealing temperatures as well as temperature(s) for dHPLC evaluation for appropriate fragments are listed in Table 5. The FIBL-6 gene was too large to evaluate the entire gene for variants; therefore, a tandem repeats finder program (51Go) was used to identify potential repeat polymorphisms and a potential tetranucleotide polymorphism was detected in intron 58. The search for variants in the RGS16 gene was conducted by SSCP of PCR amplified fragments covering all five exons of the gene. Each fragment was heat denatured and single stranded fragments resolved on a precast 6% TBE NuPAGE Novex polyacrylamide gel (Invitrogen). Unique conformers were selected for sequencing. The search for variants in the PRELP gene was conducted by PCR amplification of each of the three exons of the gene then evaluated by dHPLC using the WAVE DNA fragment analysis system (transgenomic). The reference sequences for the PCR generated fragments were obtained from the UCSC genome bioinformatics website (genome.ucsc.edu) using the human genome browser gateway and imported into the WAVE Maker software version 4.0 (transgenomic) for the generation of an appropriate melting temperature. The injected sample was 10 µl of the PCR product and a modified buffer gradient was used, which went from 35 to 59% buffer B (0.1 M TEAA/25% acetonitrile), while simultaneously going from 65 to 41% buffer A (0.1 M TEAA) with a constant flow rate of 0.9 ml/min. The volume of the injection loop of the autosampler was 100 µl, the waste volume was 50 µl and the run time was 14.0 min/sample using the fast clean setting for the accelerator. Initially, five pools of ten unrelated DNA samples were utilized for dHPLC, allowing for the detection of any variant with an allele frequency of at least 1%. When a variant chromatogram was detected from the pooled samples, all of the individual samples in the pool were evaluated and the variant samples selected for sequencing. Variants identified by dHPLC and SSCP were sequenced using dRhodamine dye terminator cycle sequencing reactions on the ABI377 (Applied Biosystems).


View this table:
[in this window]
[in a new window]
  		Table 5. Primer, annealing and dHPLC temperatures for evaluation of genes for informative variants
 
Genotyping methods
Five different genotyping methods were used over the course of this project. These include RFLP, fluorescent PCR for STR sizing, dHPLC, TaqMan and insertion/deletion evaluation. Two unrelated CEPH samples were genotyped for each variant and included on each gel, in each dHPLC run and in each TaqMan tray to assure internal consistency in genotype calls. In addition, double-masked genotyping assignments were made for each variant, compared and each discrepancy addressed using raw data or regenotyping. Table 6 lists the techniques and reaction conditions for each variant that used RFLP or fragment size analysis for genotype assignment.
  • Size-based variant evaluation. STR variants were genotyped by sizing fragments using the ABI377 and genotyper 2.5 software (Applied Biosystems).
  • dHPLC evaluation. The Met299Val SNP within exon 6 of ELOVL4 was genotyped for sporadic cases and controls using RFLP and dHPLC was utilized to genotype familial subjects. Using dHPLC, heterozygotes were initially identified and genotyped by the presence of heteroduplexes. Samples demonstrating homoduplexes were spiked with a known met/met homozygote and samples resulting in heteroduplex formation were genotyped as val/val homozygotes and those that remained homoduplex were genotyped as met/met homozygotes.
  • TaqMan evaluation. Genotype data was collected using 5' exonuclease assay-on-Demand TaqMan assays (Applied Biosystems) for variants selected for the ITGB4 (rs820168), GRLX2 (rs6665069), OCLM (hCV1462335), TGFB2 (rs2009112), one of the APOH (rs1544556) SNPs and CFH (rs10922093). Amplification and genotype assignments were conducted using the ABI7000 and SDS 2.0 software (Applied Biosystems).


View this table:
[in this window]
[in a new window]
  		Table 6. Method and reaction conditions for genotyping using RFLP or fragment size analysis.
 
Statistical analyses: error checking
For the family data, genotypes at each locus were checked for Mendelian inconsistencies with the use of PedCheck (52Go), which uses genotype elimination to identify subtle inconsistencies.

Allele frequency estimation
Allele frequencies were estimated separately using all family members and only Type A affected family members using Mendel version 5 (53Go). This approach properly takes all known familial relationships into account, while estimating the allele frequencies. For the unrelated cases and controls, allele frequencies were estimated by allele counting.

Tests for HWE
For the two-allele SNPs, we tested for HWE using an exact test (54Go) as implemented in the HWE exact function of the R genetics package (55Go,56Go); empirical P-values were estimated by simulation with 10 000 replicates. For the three multi-allelic markers, we tested for HWE using the Markov Chain Monte Carlo approach of Guo and Thompson (57Go), which is implemented in Mega2 (58Go). This approach can more properly handle the sparse tables encountered when analyzing multiallelic markers.

Analysis of case–control data
Using the unrelated cases and the unrelated controls, we tested for association between the variants and the ARM disease status. {chi}2 tests were done using the {chi}2 function of the R package and simulated P-values using 10 000 replicates were obtained. For the three multi-allelic markers, the T4 test of CLUMP package (59Go) was used. The T4 test seeks the grouping of alleles that maximizes the {chi}2 statistic and adjusts for the multiple testing by using simulation to generate empirical P-values.

Case–control and family data
Association testing for SNPs using the combined family and case–control data was done using the case–control association analysis of pedigree data (CCREL) (43Go). While testing for association, this approach permits one to use related individuals in the family data by calculating the effective number of cases. Independent cases and controls can also be used in this analysis. CCREL allows us to perform haplotype-based association for a window width of a maximum of three markers. For the APOHin6, APOH154 and APOH266 variants within the APOH gene and rs10922093 and Tyr402His variants within the CFH gene haplotype-based association testing was carried out and the P-values reported. R package for the analysis (CCREL) were provided by the authors (43Go), but, as currently implemented, this is only applicable to two-allele systems. TDT or PDT type analyses are not feasible for our data, since such testing requires that parents be genotyped, which we essentially have none due to the late onset of AMD.

Multiple testing issues
To provide a measure of the impact of multiple testing, we employ the FDR approach of Benjamini and Hochberg (44Go) and Storey (45Go), as implemented in the fdr.control program of the R library Gene TS (60Go). The FDR approach controls the expected proportion of false positives among the significant tests.


   ACKNOWLEDGEMENTS
 
We want to especially acknowledge the study participants and their families for participating in this study. We also very much appreciate the efforts of Margaret Pericak-Vance, Jonathan Haines and their colleagues who provided advance notification of their findings regarding CFH, which prompted us to complete analysis of the CFH data that we had already generated as part of this candidate gene study. This study was supported by NEI grant R01EY009859, The Steinbach Foundation, New York, Research to Prevent Blindness, New York and the Eye and Ear Foundation of Pittsburgh (all to M.B.G.). A.T. was supported by the India–US Research Training Program in Genetics, which is sponsored by Fogarty International Center/NIH grant 5D43TW006180 (Program Directors: D.E.W. and P.P. Majumder).

Conflict of Interest statement. None declared.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 RESULTS
 DISCUSSION
 MATERIALS AND METHODS
 REFERENCES
 

  1. The Eye Diseases Prevalence Research Group (2004) Causes and prevalence of visual impairment among adults in the United States. Arch. Ophthalmol., 122, 477–485.[Abstract/Free Full Text]

  2. Hammond, C.J., Webster, A.R., Snieder, H., Bird, A.C., Gilbert, C.E. and Spector, T.D. (2002) Genetic influence on early age-related maculopathy: a twin study. Ophthalmology, 109, 730–736.[CrossRef][Web of Science][Medline]

  3. Weeks, D.E., Conley, Y.P., Tsai, H.J., Mah, T.S., Schmidt, S., Postel, E.A., Agarwal, A., Haines, J.L., Pericak-Vance, M.A., Rosenfeld, P.J. et al. (2004) Age-related maculopathy: a genomewide scan with continued evidence of susceptibility loci within the 1q31, 10q26, and 17q25 regions. Am. J. Hum. Genet., 75, 174–189.[CrossRef][Web of Science][Medline]

  4. Weeks, D.E., Conley, Y.P., Tsai, H.J., Mah, T.S., Rosenfeld, P.J., Paul, T.O., Eller, A.W., Morse, L.S., Dailey, J.P., Ferrell, R.E. et al. (2001) Age-related maculopathy: an expanded genome-wide scan with evidence of susceptibility loci within the 1q31 and 17q25 regions. Am. J. Ophthalmol., 132, 682–692.[CrossRef][Web of Science][Medline]

  5. Klein, M.L., Schultz, D.W., Edwards, A., Matise, T.C., Rust, K., Berselli, C.B., Trzupek, K., Weleber, R.G., Ott, J., Wirtz, M.K. et al. (1998) Age-related macular degeneration. Clinical features in a large family and linkage to chromosome 1q. Arch. Ophthalmol., 116, 1082–1088.[Abstract/Free Full Text]

  6. Majewski, J., Schultz, D.W., Weleber, R.G., Schain, M.B., Edwards, A.O., Matise, T.C., Acott, T.S., Ott, J. and Klein, M.L. (2003) Age-related macular degeneration—a genome scan in extended families. Am. J. Hum. Genet., 73, 540–550.[CrossRef][Web of Science][Medline]

  7. Iyengar, S.K., Song, D., Klein, B.E., Klein, R., Schick, J.H., Humphrey, J., Millard, C., Liptak, R., Russo, K., Jun, G. et al. (2004) Dissection of genomewide-scan data in extended families reveals a major locus and oligogenic susceptibility for age-related macular degeneration. Am. J. Hum. Genet., 74, 20–39.[CrossRef][Web of Science][Medline]

  8. Seddon, J.M., Santangelo, S.L., Book, K., Chong, S. and Cote, J. (2003) A genomewide scan for age-related macular degeneration provides evidence for linkage to several chromosomal regions. Am. J. Hum. Genet., 73, 780–790.[CrossRef][Web of Science][Medline]

  9. Abecasis, G.R., Yashar, B.M., Zhao, Y., Ghiasvand, N.M., Zareparsi, S., Branham, K.E., Reddick, A.C., Trager, E.H., Yoshida, S., Bahling, J. et al. (2004) Age-related macular degeneration: a high-resolution genome scan for susceptibility loci in a population enriched for late-stage disease. Am. J. Hum. Genet., 74, 482–494.[CrossRef][Web of Science][Medline]

  10. Kenealy, S.J., Schmidt, S., Agarwal, A., Postel, E.A., De La Paz, M.A., Pericak-Vance, M.A. and Haines, J.L. (2004) Linkage analysis for age-related macular degeneration supports a gene on chromosome 10q26. Mol. Vis., 10, 57–61.[Web of Science][Medline]

  11. Weeks, D.E., Conley, Y.P., Mah, T.S., Paul, T.O., Morse, L., Ngo-Chang, J., Dailey, J.P., Ferrell, R.E. and Gorin, M.B. (2000) A full genome scan for age-related maculopathy. Hum. Mol. Genet., 9, 1329–1349.[Abstract/Free Full Text]

  12. Schultz, D.W., Klein, M.L., Humpert, A.J., Luzier, C.W., Persun, V., Schain, M., Mahan, A., Runckel, C., Cassera, M., Vittal, V. et al. (2003) Analysis of the ARMD1 locus: evidence that a mutation in HEMICENTIN-1 is associated with age-related macular degeneration in a large family. Hum. Mol. Genet., 12, 3315–3323.[Abstract/Free Full Text]

  13. Stone, E.M., Lotery, A.J., Munier, F.L., Heon, E., Piguet, B., Guymer, R.H., Vandenburgh, K., Cousin, P., Nishimura, D., Swiderski, R.E. et al. (1999) A single EFEMP1 mutation associated with both Malattia Leventinese and Doyne honeycomb retinal dystrophy. Nat. Genet., 22, 199–202.[CrossRef][Web of Science][Medline]

  14. Zhang, K., Kniazeva, M., Han, M., Li, W., Yu, Z., Yang, Z., Li, Y., Metzker, M.L., Allikmets, R., Zack, D.J. et al. (2001) A 5 bp deletion in ELOVL4 is associated with two related forms of autosomal dominant macular dystrophy. Nat. Genet., 27, 89–93.[Web of Science][Medline]

  15. Bernstein, P.S., Tammur, J., Singh, N., Hutchinson, A., Dixon, M., Pappas, C.M., Zabriskie, N.A., Zhang, K., Petrukhin, K., Leppert, M. et al. (2001) Diverse macular dystrophy phenotype caused by a novel complex mutation in the ELOVL4 gene. Invest. Ophthalmol. Vis. Sci., 42, 3331–3336.[Abstract/Free Full Text]

  16. Maugeri, A., Meire, F., Hoyng, C.B., Vink, C., Van Regemorter, N., Karan, G., Yang, Z., Cremers, F.P. and Zhang, K. (2004) A novel mutation in the ELOVL4 gene causes autosomal dominant Stargardt-like macular dystrophy. Invest. Ophthalmol. Vis. Sci., 45, 4263–4267.[Abstract/Free Full Text]

  17. Hamdi, H.K., Reznik, J., Castellon, R., Atilano, S.R., Ong, J.M., Udar, N., Tavis, J.H., Aoki, A.M., Nesburn, A.B., Boyer, D.S. et al. (2002) Alu DNA polymorphism in ACE gene is protective for age-related macular degeneration. Biochem. Biophys. Res. Commun., 295, 668–672.[CrossRef][Web of Science][Medline]

  18. Souied, E.H., Benlian, P., Amouyel, P., Feingold, J., Lagarde, J.P., Munnich, A., Kaplan, J., Coscas, G. and Soubrane, G. (1998) The epsilon4 allele of the apolipoprotein E gene as a potential protective factor for exudative age-related macular degeneration. Am. J. Ophthalmol., 125, 353–359.[CrossRef][Web of Science][Medline]

  19. Klaver, C.C., Kliffen, M., van Duijn, C.M., Hofman, A., Cruts, M., Grobbee, D.E., van Broeckhoven, C. and de Jong, P.T. (1998) Genetic association of apolipoprotein E with age-related macular degeneration. Am. J. Hum. Genet., 63, 200–206.[CrossRef][Web of Science][Medline]

  20. Schmidt, S., Klaver, C., Saunders, A., Postel, E., De La Paz, M., Agarwal, A., Small, K., Udar, N., Ong, J., Chalukya, M. et al. (2002) A pooled case–control study of the apolipoprotein E (APOE) gene in age-related maculopathy. Ophthalmic. Genet., 23, 209–223.[CrossRef][Medline]

  21. Ikeda, T., Obayashi, H., Hasegawa, G., Nakamura, N., Yoshikawa, T., Imamura, Y., Koizumi, K. and Kinoshita, S. (2001) Paraoxonase gene polymorphisms and plasma oxidized low-density lipoprotein level as possible risk factors for exudative age-related macular degeneration. Am. J. Ophthalmol., 132, 191–195.[CrossRef][Web of Science][Medline]

  22. Kimura, K., Isashiki, Y., Sonoda, S., Kakiuchi-Matsumoto, T. and Ohba, N. (2000) Genetic association of manganese superoxide dismutase with exudative age-related macular degeneration. Am. J. Ophthalmol., 130, 769–773.[CrossRef][Web of Science][Medline]

  23. Zurdel, J., Finckh, U., Menzer, G., Nitsch, R.M. and Richard, G. (2002) CST3 genotype associated with exudative age related macular degeneration. Br. J. Ophthalmol., 86, 214–219.[Abstract/Free Full Text]

  24. Allikmets, R., Shroyer, N.F., Singh, N., Seddon, J.M., Lewis, R.A., Bernstein, P.S., Peiffer, A., Zabriskie, N.A., Li, Y., Hutchinson, A. et al. (1997) Mutation of the Stargardt disease gene (ABCR) in age-related macular degeneration. Science, 277, 1805–1807.[Abstract/Free Full Text]

  25. Haines, J.L., Hauser, M.A., Schmidt, S., Scott, W.K., Olson, L.M., Gallins, P., Spencer, K.L., Kwan, S.Y., Noureddine, M., Gilbert, J.R. et al. (2005) Complement factor H variant increases the risk of age-related macular degeneration. Science, 308, 419–421.[Abstract/Free Full Text]

  26. Edwards, A.O., Ritter, R., III, Abel, K.J., Manning, A., Panhuysen, C. and Farrer, L.A. (2005) Complement factor H polymorphism and age-related macular degeneration. Science, 308, 421–424.[Abstract/Free Full Text]

  27. Hageman, G.S., Anderson, D.H., Johnson, L.V., Hancox, L.S., Taiber, A.J., Hardisty, L.I., Hageman, J.L., Stockman, H.A., Borchardt, J.D., Gehrs, K.M. et al. (2005) A common haplotype in the complement regulatory gene factor H (HF1/CFH) predisposes individuals to age-related macular degeneration. Proc. Natl Acad. Sci. USA, 102, 7227–7232.[Abstract/Free Full Text]

  28. Klein, R.J., Zeiss, C., Chew, E.Y., Tsai, J.Y., Sackler, R.S., Haynes, C., Henning, A.K., Sangiovanni, J.P., Mane, S.M., Mayne, S.T. et al. (2005) Complement factor H polymorphism in age-related macular degeneration. Science, 308, 385–389.[Abstract/Free Full Text]

  29. Mullins, R.F., Russell, S.R., Anderson, D.H. and Hageman, G.S. (2000) Drusen associated with aging and age-related macular degeneration contain proteins common to extracellular deposits associated with atherosclerosis, elastosis, amyloidosis, and dense deposit disease. FASEB J., 14, 835–846.[Abstract/Free Full Text]

  30. van Leeuwen, R., Klaver, C.C., Vingerling, J.R., Hofman, A., van Duijn, C.M., Stricker, B.H. and de Jong, P.T. (2004) Cholesterol and age-related macular degeneration: is there a link? Am. J. Ophthalmol., 137, 750–752.[Web of Science][Medline]

  31. Li, C.M., Presley, J.B., Zhang, X., Dashti, N., Chung, B.H., Medeiros, N.E., Guidry, C. and Curcio, C.A. (2005) Retina expresses microsomal triglyceride transfer protein: implications for age-related maculopathy. J. Lipid. Res., 46, 628–640.[Abstract/Free Full Text]

  32. Johnson, L.V. and Anderson, D.H. (2004) Age-related macular degeneration and the extracellular matrix. N. Engl. J. Med., 351, 320–322.[Free Full Text]

  33. Green, W.R. and Enger, C. (1993) Age-related macular degeneration histopathologic studies. The 1992 Lorenz E. Zimmerman lecture. Ophthalmology, 100, 1519–1535.[Web of Science][Medline]

  34. Zarbin, M.A. (2004) Current concepts in the pathogenesis of age-related macular degeneration. Arch. Ophthalmol., 122, 598–614.[Abstract/Free Full Text]

  35. Weber, B.H., Vogt, G., Pruett, R.C., Stohr, H. and Felbor, U. (1994) Mutations in the tissue inhibitor of metalloproteinases-3 (TIMP3) in patients with Sorsby's fundus dystrophy. Nat. Genet., 8, 352–356.[CrossRef][Web of Science][Medline]

  36. Sprecher, E., Bergman, R., Richard, G., Lurie, R., Shalev, S., Petronius, D., Shalata, A., Anbinder, Y., Leibu, R., Perlman, I. et al. (2001) Hypotrichosis with juvenile macular dystrophy is caused by a mutation in CDH3, encoding P-cadherin. Nat. Genet., 29, 134–136.[CrossRef][Web of Science][Medline]

  37. Indelman, M., Bergman, R., Lurie, R., Richard, G., Miller, B., Petronius, D., Ciubutaro, D., Leibu, R. and Sprecher, E. (2002) A missense mutation in CDH3, encoding P-cadherin, causes hypotrichosis with juvenile macular dystrophy. J. Invest. Dermatol., 119, 1210–1213.[CrossRef][Web of Science][Medline]

  38. Areds, S.G. (2001) A randomized, placebo-controlled, clinical trial of high-dose supplementation with vitamins C and E, beta carotene, and zinc for age-related macular degeneration and vision loss: AREDS report no. 8. Arch. Ophthalmol., 119, 1417–1436.[Abstract/Free Full Text]

  39. Beatty, S., Koh, H., Phil, M., Henson, D. and Boulton, M. (2000) The role of oxidative stress in the pathogenesis of age-related macular degeneration. Surv. Ophthalmol., 45, 115–134.[CrossRef][Web of Science][Medline]

  40. De La Paz, M. and Anderson, R.E. (1992) Region and age-dependent variation in susceptibility of the human retina to lipid peroxidation. Invest. Ophthalmol. Vis. Sci., 33, 3497–3499.[Abstract/Free Full Text]

  41. Penfold, P.L., Killingsworth, M.C. and Sarks, S.H. (1985) Senile macular degeneration: the involvement of immunocompetent cells. Graefes. Arch. Clin. Exp. Ophthalmol., 223, 69–76.[CrossRef][Web of Science][Medline]

  42. Yamamoto, C., Ogata, N., Yi, X., Takahashi, K., Miyashiro, M., Yamada, H., Uyama, M. and Matsuzaki, K. (1998) Immunolocalization of transforming growth factor beta during wound repair in rat retina after laser photocoagulation. Graefes. Arch. Clin. Exp. Ophthalmol., 236, 41–46.[CrossRef][Web of Science][Medline]

  43. Browning, S.R., Briley, J.D., Briley, L.P., Chandra, G., Charnecki, J.H., Ehm, M.G., Johansson, K.A., Jones, B.J., Karter, A.J., Yarnall, D.P. et al. (2005) Case–control single-marker and haplotypic association analysis of pedigree data. Genet. Epidemiol., 28, 110–122.[CrossRef][Web of Science][Medline]

  44. Benjamini, Y. and Hochberg, Y. (1995) Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. Roy. Stat. Soc. Ser. B., 57, 289–300.

  45. Storey, J. (2002) A direct approach to false discovery rates. J. Roy. Stat. Soc. Ser. B., 64, 479–498.[CrossRef]

  46. Slager, S.L., Huang, J. and Vieland, V.J. (2000) Effect of allelic heterogeneity on the power of the transmission disequilibrium test. Genet. Epidemiol., 18, 143–156.[CrossRef][Web of Science][Medline]

  47. Ayyagari, R., Zhang, K., Hutchinson, A., Yu, Z., Swaroop, A., Kakuk, L.E., Seddon, J.M., Bernstein, P.S., Lewis, R.A., Tammur, J. et al. (2001) Evaluation of the ELOVL4 gene in patients with age-related macular degeneration. Ophthalmic. Genet., 22, 233–239.[CrossRef][Medline]

  48. Jozsi, M., Manuelian, T., Heinen, S., Oppermann, M. and Zipfel, P.F. (2004) Attachment of the soluble complement regulator factor H to cell and tissue surfaces: relevance for pathology. Histol. Histopathol., 19, 251–258.[Web of Science][Medline]

  49. Goodship, T. (2004) Inherited dysregulation of the complement system. Bull. Mem. Acad. R. Med. Belg., 159, 195–198.[Medline]

  50. Miller, S.A., Dykes, D.D. and Polesky, H.F. (1988) A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res., 16, 1215.[Free Full Text]

  51. Benson, G. (1999) Tandem repeats finder: a program to analyze DNA sequences. Nucleic Acids Res., 27, 573–580.[Abstract/Free Full Text]

  52. O'Connell, J.R. and Weeks, D.E. (1998) PedCheck: a program for identification of genotype incompatibilities in linkage analysis. Am. J. Hum. Genet., 63, 259–266.[CrossRef][Web of Science][Medline]

  53. Lange, K., Cantor, R., Horvath, S., Perola, M., Sabatti, C., Sinsheimer, J. and Sobel, E. (2001) Mendel version 4.0: A complete package for the exact genetic analysis of discrete traits in pedigree and population data sets. Am. J. Hum. Genet., 69, A1886.

  54. Emigh, T. (1980) Comparison of tests for Hardy–Weinberg equilibrium. Biometrics, 36, 627–642.[CrossRef][Web of Science]

  55. Warnes, G. and Leisch, F. (2004) Population Genetics. R package. 1.1.0 ed

  56. R Development Core Team (2004) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.

  57. Guo, S.W. and Thompson, E.A. (1992) Performing the exact test of Hardy–Weinberg proportion for multiple alleles. Biometrics, 48, 361–372.[CrossRef][Web of Science][Medline]

  58. Mukhopadhyay, N., Almasy, L., Schroeder, M., Mulvihill, W.P. and Weeks, D.E. (2005) Mega2: data-handling for facilitating genetic linkage and association analyses. Bioinformatics, 21, 2556–2557.[Abstract/Free Full Text]

  59. Sham, P.C. and Curtis, D. (1995) Monte Carlo tests for associations between disease and alleles at highly polymorphic loci. Ann. Hum. Genet., 59, 97–105.[Web of Science][Medline]

  60. Fokianos, K., Schaefer, J. and Strimmer, K. (2005) GeneTS: Microarry Time Series and Network Analysis. R Package version 2.4.

  61. Vogel, B.E. and Hedgecock, E.M. (2001) Hemicentin, a conserved extracellular member of the immunoglobulin superfamily, organizes epithelial and other cell attachments into oriented line-shaped junctions. Development, 128, 883–894.[Abstract]

  62. Toti, P., De Felice, C., Malandrini, A., Megha, T., Cardone, C. and Villanova, M. (1997) Localization of laminin chains in the human retina: possible implications for congenital muscular dystrophy associated with alpha 2-chain of laminin deficiency. Neuromuscul. Disord., 7, 21–25.[CrossRef][Web of Science][Medline]

  63. Chen, C.K., Wieland, T. and Simon, M.I. (1996) RGS-r, a retinal specific RGS protein, binds an intermediate conformation of transducin and enhances recycling. Proc. Natl Acad. Sci. USA, 93, 12885–12889.[Abstract/Free Full Text]

  64. Snow, B.E., Antonio, L., Suggs, S. and Siderovski, D.P. (1998) Cloning of a retinally abundant regulator of G-protein signaling (RGS-r/RGS16): genomic structure and chromosomal localization of the human gene. Gene, 206, 247–253.[CrossRef][Web of Science][Medline]

  65. Sato, Y., Matsuo, T. and Ohtsuki, H. (1999) A novel gene (oculomedin) induced by mechanical stretching in human trabecular cells of the eye. Biochem. Biophys. Res. Commun., 259, 349–351.[CrossRef][Web of Science][Medline]

  66. Gladyshev, V.N., Liu, A., Novoselov, S.V., Krysan, K., Sun, Q.A., Kryukov, V.M., Kryukov, G.V. and Lou, M.F. (2001) Identification and characterization of a new mammalian glutaredoxin (thioltransferase), Grx2. J. Biol. Chem., 276, 30374–30380.[Abstract/Free Full Text]

  67. Wu, F., Wang, G.M., Raghavachari, N. and Lou, M.F. (1998) Distribution of thioltransferase (glutaredoxin) in ocular tissues. Invest. Ophthalmol. Vis. Sci., 39, 476–480.[Abstract/Free Full Text]

  68. Bengtsson, E., Morgelin, M., Sasaki, T., Timpl, R., Heinegard, D. and Aspberg, A. (2002) The leucine-rich repeat protein PRELP binds perlecan and collagens and may function as a basement membrane anchor. J. Biol. Chem., 277, 15061–15068.[Abstract/Free Full Text]

  69. Sanchez-Corral, P., Gonzalez-Rubio, C., Rodriguez de Cordoba, S. and Lopez-Trascasa, M. (2004) Functional analysis in serum from atypical hemolytic uremic syndrome patients reveals impaired protection of host cells associated with mutations in factor H. Mol. Immunol., 41, 81–84.[CrossRef][Web of Science][Medline]

  70. Rodriguez de Cordoba, S., Esparza-Gordillo, J., Goicoechea de Jorge, E., Lopez-Trascasa, M. and Sanchez-Corral, P. (2004) The human complement factor H: functional roles, genetic variations and disease associations. Mol. Immunol., 41, 355–367.[CrossRef][Web of Science][Medline]

  71. DiScipio, R.G., Daffern, P.J., Schraufstatter, I.U. and Sriramarao, P. (1998) Human polymorphonuclear leukocytes adhere to complement factor H through an interaction that involves alphaMbeta2 (CD11b/CD18). J. Immunol., 160, 4057–4066.[Abstract/Free Full Text]

  72. Priglinger, S.G., May, C.A., Neubauer, A.S., Alge, C.S., Schonfeld, C.L., Kampik, A. and Welge-Lussen, U. (2003) Tissue transglutaminase as a modifying enzyme of the extracellular matrix in PVR membranes. Invest. Ophthalmol. Vis. Sci., 44, 355–364.[Abstract/Free Full Text]

  73. Tacken, P.J., Hofker, M.H., Havekes, L.M. and van Dijk, K.W. (2001) Living up to a name: the role of the VLDL receptor in lipid metabolism. Curr. Opin. Lipidol., 12, 275–279.[CrossRef][Web of Science][Medline]

  74. Tiret, L., Rigat, B., Visvikis, S., Breda, C., Corvol, P., Cambien, F. and Soubrier, F. (1992) Evidence, from combined segregation and linkage analysis, that a variant of the angiotensin I-converting enzyme (ACE) gene controls plasma ACE levels. Am. J. Hum. Genet., 51, 197–205.[Web of Science][Medline]

  75. Gu, W., Ray, K., Pearce-Kelling, S., Baldwin, V.J., Langston, A.A., Ray, J., Ostrander, E.A., Acland, G.M. and Aguirre, G.D. (1999) Evaluation of the APOH gene as a positional candidate for prcd in dogs. Invest. Ophthalmol. Vis. Sci., 40, 1229–1237.[Abstract/Free Full Text]

  76. Jonkman, M.F., Pas, H.H., Nijenhuis, M., Kloosterhuis, G. and Steege, G. (2002) Deletion of a cytoplasmic domain of integrin beta4 causes epidermolysis bullosa simplex. J. Invest. Dermatol., 119, 1275–1281.[CrossRef][Web of Science][Medline]

  77. Boyles, J.K., Zoellner, C.D., Anderson, L.J., Kosik, L.M., Pitas, R.E., Weisgraber, K.H., Hui, D.Y., Mahley, R.W., Gebicke-Haerter, P.J., Ignatius, M.J. et al. (1989) A role for apolipoprotein E, apolipoprotein A-I, and low density lipoprotein receptors in cholesterol transport during regeneration and remyelination of the rat sciatic nerve. J. Clin. Invest., 83, 1015–1031.[Web of Science][Medline]

  78. Mahley, R.W. (1988) Apolipoprotein E: cholesterol transport protein with expanding role in cell biology. Science, 240, 622–630.[Abstract/Free Full Text]

  79. Kontula, K., Aalto-Setala, K., Kuusi, T., Hamalainen, L. and Syvanen, A.C. (1990) Apolipoprotein E polymorphism determined by restriction enzyme analysis of DNA amplified by polymerase chain reaction: convenient alternative to phenotyping by isoelectric focusing. Clin. Chem., 36, 2087–2092.[Abstract/Free Full Text]

  80. Okuizumi, K., Onodera, O., Namba, Y., Ikeda, K., Yamamoto, T., Seki, K., Ueki, A., Nanko, S., Tanaka, H. and Takahashi, H. (1995) Genetic association of the very low density lipoprotein (VLDL) receptor gene with sporadic Alzheimer's disease. Nat. Genet., 11, 207–209.[CrossRef][Web of Science][Medline]


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 IOVSHome page
G. Wang, K. L. Spencer, B. L. Court, L. M. Olson, W. K. Scott, J. L. Haines, and M. A. Pericak-Vance
Localization of Age-Related Macular Degeneration-Associated ARMS2 in Cytosol, Not Mitochondria
Invest. Ophthalmol. Vis. Sci., July 1, 2009; 50(7): 3084 - 3090.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
N. Udar, S. R. Atilano, M. Memarzadeh, D. S. Boyer, M. Chwa, S. Lu, B. Maguen, J. Langberg, P. Coskun, D. C. Wallace, et al.
Mitochondrial DNA Haplogroups Associated with Age-Related Macular Degeneration
Invest. Ophthalmol. Vis. Sci., June 1, 2009; 50(6): 2966 - 2974.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
J. Zhou, S. R. Kim, B. S. Westlund, and J. R. Sparrow
Complement Activation by Bisretinoid Constituents of RPE Lipofuscin
Invest. Ophthalmol. Vis. Sci., March 1, 2009; 50(3): 1392 - 1399.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
N. R. Kim, J. H. Kang, O. W. Kwon, S. J. Lee, J. H. Oh, and H. S. Chin
Association between Complement Factor H Gene Polymorphisms and Neovascular Age-Related Macular Degeneration in Koreans
Invest. Ophthalmol. Vis. Sci., May 1, 2008; 49(5): 2071 - 2076.
[Abstract] [Full Text] [PDF]

Home page
 GeneticsHome page
Y. Cui, G. Kang, K. Sun, M. Qian, R. Romero, and W. Fu
Gene-Centric Genomewide Association Study via Entropy
Genetics, May 1, 2008; 179(1): 637 - 650.
[Abstract] [Full Text] [PDF]

Home page
 Hum Mol GenetHome page
L. Fu, D. Garland, Z. Yang, D. Shukla, A. Rajendran, E. Pearson, E. M. Stone, K. Zhang, and E. A. Pierce
The R345W mutation in EFEMP1 is pathogenic and causes AMD-like deposits in mice
Hum. Mol. Genet., October 15, 2007; 16(20): 2411 - 2422.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
A. Kanda, W. Chen, M. Othman, K. E. H. Branham, M. Brooks, R. Khanna, S. He, R. Lyons, G. R. Abecasis, and A. Swaroop
A variant of mitochondrial protein LOC387715/ARMS2, not HTRA1, is strongly associated with age-related macular degeneration
PNAS, October 9, 2007; 104(41): 16227 - 16232.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
K. L. Spencer, M. A. Hauser, L. M. Olson, N. Schnetz-Boutaud, W. K. Scott, S. Schmidt, P. Gallins, A. Agarwal, E. A. Postel, M. A. Pericak-Vance, et al.
Haplotypes Spanning the Complement Factor H Gene Are Protective against Age-Related Macular Degeneration
Invest. Ophthalmol. Vis. Sci., September 1, 2007; 48(9): 4277 - 4283.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
J. Tuo, C. M. Bojanowski, M. Zhou, D. Shen, R. J. Ross, K. I. Rosenberg, D. J. Cameron, C. Yin, J. A. Kowalak, Z. Zhuang, et al.
Murine Ccl2/Cx3cr1 Deficiency Results in Retinal Lesions Mimicking Human Age-Related Macular Degeneration
Invest. Ophthalmol. Vis. Sci., August 1, 2007; 48(8): 3827 - 3836.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
G. Thomas, M. A. Grassi, J. R. Lee, A. O. Edwards, M. B. Gorin, R. Klein, T. L. Casavant, T. E. Scheetz, E. M. Stone, and A. B. Williams
IDOCS: Intelligent Distributed Ontology Consensus System--The Use of Machine Learning in Retinal Drusen Phenotyping
Invest. Ophthalmol. Vis. Sci., May 1, 2007; 48(5): 2278 - 2284.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
D. A. Schaumberg, W. G. Christen, J. E. Buring, R. J. Glynn, N. Rifai, and P. M. Ridker
High-Sensitivity C-Reactive Protein, Other Markers of Inflammation, and the Incidence of Macular Degeneration in Women
Arch Ophthalmol, March 1, 2007; 125(3): 300 - 305.
[Abstract] [Full Text] [PDF]

Home page
 Am J EpidemiolHome page
A. Shankar, P. Mitchell, E. Rochtchina, J. Tan, and J. J. Wang
Association between Circulating White Blood Cell Count and Long-Term Incidence of Age-related Macular Degeneration: The Blue Mountains Eye Study
Am. J. Epidemiol., February 15, 2007; 165(4): 375 - 382.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
M. B. Gorin
A Clinician's View of the Molecular Genetics of Age-Related Maculopathy
Arch Ophthalmol, January 1, 2007; 125(1): 21 - 29.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
M. M. DeAngelis, F. Ji, I. K. Kim, S. Adams, A. Capone Jr, J. Ott, J. W. Miller, and T. P. Dryja
Cigarette Smoking, CFH, APOE, ELOVL4, and Risk of Neovascular Age-Related Macular Degeneration
Arch Ophthalmol, January 1, 2007; 125(1): 49 - 54.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
D. A. Schaumberg, S. E. Hankinson, Q. Guo, E. Rimm, and D. J. Hunter
A Prospective Study of 2 Major Age-Related Macular Degeneration Susceptibility Alleles and Interactions With Modifiable Risk Factors
Arch Ophthalmol, January 1, 2007; 125(1): 55 - 62.
[Abstract] [Full Text] [PDF]

Home page
 Hum Mol GenetHome page
Y. P. Conley, J. Jakobsdottir, T. Mah, D. E. Weeks, R. Klein, L. Kuller, R. E. Ferrell, and M. B. Gorin
CFH, ELOVL4, PLEKHA1 and LOC387715 genes and susceptibility to age-related maculopathy: AREDS and CHS cohorts and meta-analyses
Hum. Mol. Genet., November 1, 2006; 15(21): 3206 - 3218.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
P. N. Baird, F. M. A. Islam, A. J. Richardson, M. Cain, N. Hunt, and R. Guymer
Analysis of the Y402H Variant of the Complement Factor H Gene in Age-Related Macular Degeneration.
Invest. Ophthalmol. Vis. Sci., October 1, 2006; 47(10): 4194 - 4198.
[Abstract] [Full Text] [PDF]

Home page
 Hum Mol GenetHome page
A. Thakkinstian, P. Han, M. McEvoy, W. Smith, J. Hoh, K. Magnusson, K. Zhang, and J. Attia
Systematic review and meta-analysis of the association between complementary factor H Y402H polymorphisms and age-related macular degeneration
Hum. Mol. Genet., September 15, 2006; 15(18): 2784 - 2790.
[Abstract] [Full Text] [PDF]

Home page
 Br J OphthalmolHome page
G Malek and S W Cousins
Is our current clinical classification of AMD up to the job?
Br J Ophthalmol, September 1, 2006; 90(9): 1080 - 1081.
[Full Text] [PDF]

Home page
 Br J OphthalmolHome page
F Simonelli, G Frisso, F Testa, R di Fiore, D F Vitale, M P Manitto, R Brancato, E Rinaldi, and L Sacchetti
Polymorphism p.402Y>H in the complement factor H protein is a risk factor for age related macular degeneration in an Italian population
Br J Ophthalmol, September 1, 2006; 90(9): 1142 - 1145.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
L.-I. Lau, S.-J. Chen, C.-Y. Cheng, M.-Y. Yen, F.-L. Lee, M.-W. Lin, W.-M. Hsu, and Y.-H. Wei
Association of the Y402H Polymorphism in Complement Factor H Gene and Neovascular Age-Related Macular Degeneration in Chinese Patients.
Invest. Ophthalmol. Vis. Sci., August 1, 2006; 47(8): 3242 - 3246.
[Abstract] [Full Text] [PDF]

Home page
 Br J OphthalmolHome page
N Dashti, G McGwin, C Owsley, and C A Curcio
Plasma apolipoproteins and risk for age related maculopathy
Br J Ophthalmol, August 1, 2006; 90(8): 1028 - 1033.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
J. Tuo, B. Ning, C. M. Bojanowski, Z.-N. Lin, R. J. Ross, G. F. Reed, D. Shen, X. Jiao, M. Zhou, E. Y. Chew, et al.
Synergic effect of polymorphisms in ERCC6 5' flanking region and complement factor H on age-related macular degeneration predisposition
PNAS, June 13, 2006; 103(24): 9256 - 9261.
[Abstract] [Full Text] [PDF]

Home page
 IOVSHome page
D. A. Schaumberg, W. G. Christen, P. Kozlowski, D. T. Miller, P. M. Ridker, and R. Y. L. Zee
A Prospective Assessment of the Y402H Variant in Complement Factor H, Genetic Variants in C-Reactive Protein, and Risk of Age-Related Macular Degeneration.
Invest. Ophthalmol. Vis. Sci., June 1, 2006; 47(6): 2336 - 2340.
[Abstract] [Full Text] [PDF]

Home page
 Arch OphthalmolHome page
J. L. Wiggs
Complement factor h and macular degeneration: the genome yields an important clue.
Arch Ophthalmol, April 1, 2006; 124(4): 577 - 578.
[Full Text] [PDF]

Home page
 Hum Mol GenetHome page
A. Rivera, S. A. Fisher, L. G. Fritsche, C. N. Keilhauer, P. Lichtner, T. Meitinger, and B. H.F. Weber
Hypothetical LOC387715 is a second major susceptibility gene for age-related macular degeneration, contributing independently of complement factor H to disease risk
Hum. Mol. Genet., November 1, 2005; 14(21): 3227 - 3236.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
14/14/1991    most recent
ddi204v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (59)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Conley, Y. P.
Right arrow Articles by Gorin, M. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Conley, Y. P.
Right arrow Articles by Gorin, M. B.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?