Linkage analysis and mutation screening of the rhodopsin gene in a Chinese Bai family with autosomal dominant retinitis pigmentosa

Autosomal dominant retinitis pigmentosa (adRP) is a common form of RP worldwide. Although rhodopsin (RHO) is the most frequently reported adRP gene in many populations, it has not been detected in patients from the Bai nationality, one of the minority ethnic groups of southwest China. In this study, we used linkage analysis and mutation screening to identify the RHO gene in a Chinese Bai family with adRP. We found that in all affected members of the Bai family, the maximum two-point logarithm of odds score obtained was 3.61 and 4.52 at a recombination fraction (θ) of zero, with markers D3S3606 and D3S1292, respectively. Haplotype analysis showed cosegregation at the 1-c region harboring the RHO gene between the two markers with the disease. Direct sequencing of RHO revealed a c.1040C>T (p.Pro347leu) mutation in exon 5, which was supported by the reaction of the restriction enzyme. Two nonpathogenic single-nucleotide polymorphisms, rs7984 and rs2269736, were found in exon 1. To the best of our knowledge, this is the first genetic analysis of a Chinese Bai family with adRP, and a known missense RHO mutation (p.Pro347leu) is responsible for it.