Human Molecular Genetics Advance Access originally published online on August 7, 2008
Human Molecular Genetics 2008 17(21):3392-3398; doi:10.1093/hmg/ddn233
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Analysis of genome-wide copy number variation in Irish and Dutch ALS populations
1 Department of Clinical Neurological Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland 2 Department of Neurology, Beaumont Hospital, Dublin, Ireland 3 Department of Neurology 4 Department of Medical Genetics, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands 5 Department of Human Genetics, Neuropsychiatric Institute, University of California, Los Angeles, USA 6 Smurfit Institute of Genetics 7 Trinity College Institute of Neurosciences, Trinity College, Dublin, Ireland
* To whom correspondence should be addressed at: The Irish ALS Research Group, Department of Neurology, Beaumont Hospital, Dublin 9, Ireland. Tel: +353 18092174; Fax: +353 18092302; Email: scronin{at}rcsi.ie
Received May 19, 2008; Revised July 14, 2008; Accepted August 6, 2008
Amyotrophic lateral sclerosis (ALS) is an unrelenting neurodegenerative condition characterized by adult-onset loss of motor neurons. Genetic risk factors have been implicated in ALS susceptibility. Copy number variants (CNVs) account for more inter-individual genetic variation than SNPs and have the capacity to alter gene dose and phenotype. We sought to identify the contribution both of commonly polymorphic CNVs and rare ALS-specific CNVs to sporadic ALS (SALS). Using high-density genome-wide data from 408 Irish individuals and 868 Dutch individuals and the QuantiSNP CNV-detection algorithm, we showed that no common CNV locus is significantly associated with ALS risk. However, we identified 39 recurrent CNV loci and 16 replicated ALS-specific gene dose alterations that occur exclusively in patients with ALS and do not occur in more than 11 000 previously identified CNVs in the Database of Genomic Variation. Ataxin genes and the hereditary haemochromatosis locus were implicated along with ENSG00000176605, an uncharacterized gene on chromosome 14. Our data support the hypothesis that multiple rare CNVs may contribute risk for SALS. Future work should seek to profile the contribution of CNVs located in regions not covered on the present SNP platforms.
The authors wish it to be known that, in their opinion, the first two authors should be regarded as joint First Authors and the last two authors should be regarded as joint Last Authors.