Identification of a novel homozygous variant in the CNGA1 gene in a Chinese family with autosomal recessive retinitis pigmentosa

Retinitis pigmentosa (RP) is a complex group of hereditary retinal dystrophies. Although >60 genes have been identified to be associated with non-syndromic RP, the exact genetic variant remains elusive in numerous cases of RP. In the present study, a Chinese pedigree affected by RP with autosomal recessive inheritance, including a total of seven members with one affected patient and six unaffected individuals, was recruited. Comprehensive ophthalmic examinations were performed on the proband and the proband's unaffected daughter. Genomic DNA was extracted from peripheral blood. Whole-exome sequencing (WES) was performed for the affected individual. The candidate pathogenic variant was verified by direct Sanger sequencing. The affected individual presented with classical clinical symptoms of RP. A novel homozygous variant, c.265delC (p.L89Ffs*3) in the cyclic nucleotide-gated channel subunit α 1 gene was identified in the affected patient. This homozygous variant was absent in other unaffected family members and 600 ethnicity-matched healthy controls. The variant was co-segregated with the disease phenotype in an autosomal recessive manner.