Molecular genetics of cone-rod dystrophy in Chinese patients: New data from 61 probands and mutation overview of 163 probands.

Cone-rod dystrophy (CORD) is a common form of inherited retinal degeneration. Previously, we have conducted serial mutational analysis in probands with CORD either by Sanger sequencing or whole exome sequencing (WES). In the current study, variants in all genes from RetNet were selected from the whole exome sequencing data of 108 CORD probands (including 61 probands reported here for the first time) and were analyzed by multistep bioinformatics analysis, followed by Sanger sequencing and segregation validation. Data from the previous studies and new data from this study (163 probands in total) were summarized to provide an overview of the molecular genetics of CORD. The following potentially pathogenic mutations were identified in 93 of the 163 (57.1%) probands: CNGA3 (32.5%), ABCA4 (3.8%), ALMS1 (3.1%), GUCY2D (3.1%), CACNA1F (2.5%), CRX (1.8%), PDE6C (1.8%), CNGB3 (1.8%), GUCA1A (1.2%), UNC119 (0.6%), RPGRIP1 (1.2%), RDH12 (0.6%), KCNV2 (0.6%), C21orf2 (0.6%), CEP290 (0.6%), USH2A (0.6%) and SNRNP200 (0.6%). The 17 genes with mutations included 12 known CORD genes and five genes (ALMS1, RDH12, CEP290, USH2A, and SNRNP200) associated with other forms of retinal degeneration. Mutations in CNGA3 is most common in this cohort. This is a systematic molecular genetic analysis of Chinese patients with CORD.