Human Molecular Genetics Advance Access originally published online on July 30, 2007
Human Molecular Genetics 2007 16(20):2423-2432; doi:10.1093/hmg/ddm199
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Formation and progression of sub-retinal pigment epithelium deposits in Efemp1 mutation knock-in mice: a model for the early pathogenic course of macular degeneration
1 Department of Ophthalmology and Vision Science, 2 Department of Physiology, 3 Optical Sciences Center, University of Arizona, Tucson, AZ 85711, USA, 4 Research Service, Cleveland VA Medical Center, 5 Cole Eye Institute, Cleveland Clinic Foundation, 6 Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA and 7 Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR, USA
* To whom correspondence should be addressed at: Department of Ophthalmology and Vision Science, University of Arizona, 655 N Alvernon Way, Suite 108, Tucson, AZ 85711, USA. Tel: +1 5206260447; Fax: +1 5206260457; Email: Lmarmorstein{at}eyes.arizona.edu
Received June 14, 2007; Accepted July 17, 2007
Malattia leventinese (ML) is a dominantly inherited macular degenerative disease characterized by the presence of sub-retinal pigment epithelium (RPE) deposits. With the exception of an earlier age of onset, ML patients exhibit symptoms and histopathology compatible with the diagnosis of age-related macular degeneration (AMD), the most common cause of incurable blindness. ML is caused by a mutation (R345W) in the gene EFEMP1 which encodes fibulin-3, a protein of unknown function. We generated a knock-in mouse carrying the disease-associated mutation in the murine Efemp1 gene. Small, isolated sub-RPE deposits developed as early as 4 months of age in both heterozygous and homozygous knock-in mice. Over time these deposits increased in size and number eventually becoming continuous sheets. In older mice membranous debris was observed within the deposits and within Bruch’s membrane, and was accompanied by general RPE and choroidal abnormalities including degeneration, vacuolation, loss or disruption of the RPE basal infoldings, choroidal atrophy, and focal thickening of and invasion of cellular processes into Bruch’s membrane. Fibulin-3 was found to accumulate in the sub-RPE deposits. Thus, the Efemp1 knock-in mice reconstitute the most important histopathologic symptoms of both ML and AMD. We conclude that these mice are a valuable tool for studying the primary pathogenic course of basal deposits associated with macular degeneration and for testing prevention and treatment strategies for this class of diseases.