Whole-exome sequencing identified a novel mutation in CHM of a Chinese family

Abstract

Choroideraemia (CHM) is a rare X-linked progressive-inherited retinal disease. In this study, we diagnosed and explored the genetic cause in a Chinese pedigree exhibiting nyctalopia and decreased visual acuity in early life. Clinical data and peripheral blood samples were collected from available family members. Sanger sequencing of RPGR and RP2 genes, and subsequently whole-exome sequencing was carried out to investigate the molecular cause. The proband was initially diagnosed as retinitis pigmentosa and experienced night blindness at an early age and decreased visual acuity in teens. The other affected males in this family suffered from the same problem. Direct sequencing failed to reveal the genetic cause and hence a novel hemizygous mutation c.861_862insGCTT was detected by WES in CHM gene resulting in a premature stop codon and a truncated protein. Subsequently, it was confirmed by Sanger sequencing and cosegregation analysis. We describe a novel mutation c.861_862insGCTT in CHM gene in a Chinese pedigree with choroideraemia. Our study emphasizes the utilization of next-generation sequencing in the diagnosis and genetic analysis of retinal diseases.