Abstract
Abstract: :
Purpose: Autosomal dominant rhegmatogenous retinal detachment (adRRD) in several large pedigrees has been shown to be caused by stop–mutations in exon 2 of the COL2A1 gene. We have previously reported on the identification of a "Stickler–type" exon 30 stop–mutation of COL2A1 in a large family with nonsyndromic adRRD. We also found cosegregation of adRRD with a 22–cM 12q13 region containing the COL2A1 locus (lod score 6.1) in a second family, but could not find a COL2A1 mutation (Go et al. IOVS 44:4035–4043, 2003). The purpose of this study is to test small and medium–sized families with adRRD for linkage with COL2A1 and other chromosomal regions to identify new candidate genes for RRD. Due to the phenotypic overlap with adRRD we have selected loci known to be implicated in various forms of familial exudative vitreoretinopathy (FEVR). Methods: Genomic DNA was prepared from blood samples of individuals from fourteen pedigrees with 2–6 affected individuals, and haplotype analysis was performed using microsatellite markers to test linkage for chromosome 12q13 (COL2A1) and three FEVR loci on chromosome 11 (11q14, FZD4; 11q13, LRP5; 11p13–p12 , EVR3). Results: Two of the 14 families showed linkage with COL2A1, but sequence analysis did not reveal a mutation in the coding region of COL2A1. Linkage analysis for the three FEVR loci is in progress. Conclusions: A significant proportion of families with adRRD is not caused by defects in the COL2A1 gene. However, based on these and previous results, we cannot rule out the existence of an adRRD gene in the vicinity of the COL2A1 gene.
Keywords: retinal detachment • genetics • linkage analysis