Purpose: To describe the mutations of the retinitis pigmentosa 1 (RP1) gene and rhodopsin (RHO) gene in Ningxia patients with retinitis pigmentosa sine pigmento (RPSP) and the genotype-phenotype relationship of the mutations.
Methods: Detailed phenotypic characterization was performed on 20 pedigrees (4 autosomal dominant RPSP, 12 autosomal recessive RPSP and 4 unknown inheritance pattern), including family history and complete ophthalmic examinations. For genetic testing, the coding sequence and splice junctions of RP1 and RHOwere screened in 20 unrelated probands with RPSP by direct DNA sequencing. Detected variants were genotyped in family members and 300 controls by the same way.
Results: In this study, 5 variants in RP1 gene and 1 inRHOgene were detected in 20 probands. 4 missense changes (rs444772, rs446227, rs414352, rs441800) and 1 non-coding variant (rs56340615) were common SNPs and none of them showed a significant difference between groups. A missense mutation p.R1443W was identified in RP1 gene in three affected individuals from a Chinese family with autosomal dominant RPSP and was found to segregate with the phenotype in this family, suggestive of pathogenic.
Conclusions: To our knowledge, this is the fist time to detect gene mutation to cause retinitis pigmentosa sine pigmento. The identification of p.R1443W mutation cosegregating in a family with autosomal dominant RPSP highlights a new clinical manifestation of RP1 gene, whileRHO gene is not associated with RPSP in this study.