Clinical characterization and genetic mapping of North Carolina macular dystrophy

North Carolina macular dystrophy (NCMD) is an autosomal dominant macular disease, was mapped to 6q14-q16.2, the disease-causing gene has yet not been identified. It shares phenotypic similarity with age-related macular degeneration including drusen and choroidal neovascularization. We collected six families with NCMD including 75 members, and conducted clinical characterization and genetic mapping for these families. Forty-five patients were diagnosed as NCMD; all six NCMD families were mapped to MCDR1 locus using genetic linkage analysis. MCDR1 interval was refined to 3 cM (1.8mb) between D6S1716 to D6S1671 via fine mapping using microsatellite markers in these six families, all eleven annotated genes within the interval were analyzed by mutation screening in coding regions, no mutation was found, suggesting a potential novel gene or a new pathological mechanism causing NCMD. The refinement of MCDR1 locus will aid the disease-causing gene identification. Functional studies of NCMD genes should provide important insights into pathogenetic mechanisms of NCMD and age-related macular degeneration.