A New Mouse Model of Retinal Degeneration (rd15) With Retinal Outer Plexiform Dystrophy

Abstract

Abstract: : Purpose: To characterize the genetics and phenotype of a new mouse mutant with a progressive retinal degeneration mutation (rd15) that causes retinal outer plexiform layer dystrophy. Methods: While screening mouse strains and stocks at The Jackson Laboratory for genetic mouse models of human ocular disorders, we have identified a new mouse mutant with a slow progressive retinal degeneration ( allele symbol: rd15) and retinal outer plexiform layer dystrophy. The phenotype was documented using electroretinography, histology, and fundus photography, while the genetic characterization and linkage analysis were performed using linkage studies and gene identification. Results: Mice homozygous for the rd15 mutation show a normal fundus, but no rod ERG b–wave and a poor cone ERG by 4 weeks of age. Histology shows poor retinal outer plexiform layer at 5 months of age and retinal degeneration at 9 months of age. The inheritance pattern of rd15 mutant allele is autosomal recessive. Linkage studies mapped this new mutant to mouse Chromosome 7, in a region between markers D7Mit230 and D7Mit82, suggesting the human homolog may be on chromosome 19q13.3. Conclusions: The early onset of rod ERG b–wave loss and impaired retinal cone function combined with our genetic data suggest that this is a new mutation not previously described in mouse or human. Retinal degeneration 15 (rd15) may provide a novel mouse model for a retinal degeneration associated retinal outer plexiform layer dystrophy.

Keywords: retinal degenerations: hereditary • gene mapping • genetics