Novel KCNV2 Mutation in Cone Dytrophy with upernormal Rod Electroretinogram Original Reearch Article

Purpoe To decribe patient with cone dytrophy and upernormal rod electroretinogram (ERG) and earch for mutation in the recently decribed KCNV2 gene. Deign Clinical and molecular tudy. Method Patient from three familie originating from France, Morocco, and Algeria had tandard ophthalmologic examination and color viion analyi, Goldmann perimetry, International ociety for Clinical Electrophyiology of Viion (ICEV) protocol in accordance with ERG teting, autofluorecence evaluation, and optical coherence tomography 3 canning. The two coding exon of KCNV2 were polymerae chain reaction amplified and equenced. Reult All patient had the characteritic feature of upernormal, delayed rod ERG repone at the highet level of timulation and markedly reduced cone repone. In the French family, two affected iter were compound heterozygote for the recurrent c.1381G>A (Gly461Arg) mutation and for a novel c.442G>T (Glu148top) mutation. In the Moroccan family, affected member were homozygote for the novel c.1404delC mutation (Hi468fX503) and in the Algerian family, the proband wa homozygote for the novel c.1001delC mutation (Ala334fX453). In the three familie, parent were unaffected heterozygote carrier. None of the mutation were preent in 50 control chromoome. Concluion The three novel truncative mutation are likely to be null mutation leading to lo of function, with no difference in the phenotype preentation. Amino acid change are found excluively in the N-terminal fragment of the protein and in the P-loop, indicating the importance of thoe region for the function of the KCNV2 protein.