Identification of a locus for autosomal dominant high myopia on chromosome 5p13.3-p15.1 in a Chinese family

PURPOSE Myopia and its extreme form, high myopia, are common vision disorders worldwide, especially in Asia. Identifying genetic markers is a useful step toward understanding the genetic basis of high myopia, particularly in the Chinese population, where it is highly prevalent. This study was conducted to provide evidence of linkage for autosomal dominant high myopia to a locus on chromosome 5p13.3-p15.1 in a large Chinese family. METHODS After clinical evaluation, genomic DNA from 29 members of this family was genotyped. A genome-wide screen was then performed using 382 markers with an average inter-marker distance of 10 cM, and two-point linkage was analyzed using the MLINK program. Mutation analysis of the candidate genes was performed using direct sequencing. RESULTS Linkage to the known autosomal dominant high myopia loci was excluded. The genome-wide screening identified a maximum two-point LOD score of 3.71 at θ=0.00 with the microsatellite marker D5S502. Fine mapping and haplotype analysis defined a critical region of 11.69 cM between D5S2096 and D5S1986 on chromosome 5p13.3-p15.1. Sequence analysis of the candidate genes inside the linked region did not identify any causative mutations. CONCLUSIONS A genetic locus was mapped to chromosome 5p13.3-p15.1 in a large Chinese family with autosomal dominant high myopia.