Targeted exome sequencing identifies NMNAT1 variants in a family with Leber congenital amaurosis

Abstract

Objective To determine the disease-causing variants in a Chinese family with Leber congenital amaurosis(LCA)and characterize the clinical phenotypes. Methods This research was conducted at the Maternal and Child Health Hospital in Jiaxing and involved a family of which one member was an LCA patient and the other six members were not affected. Genomic DNA was extracted from the blood samples of all family members. We developed a panel for targeted exome sequencing(TES)of family members by selecting 283 known retina-related genes. Further bioinformatics analyses and Sanger sequencing were done to confirm the candidate variants. Results Ophthalmic examination of the patient showed a typical LCA phenotype. After TES and comprehensive analyses, two compound heterozygous variants(c.634G>A, p.V212M; c.-57+ 7T>G)were identified and one homozygous missense(c.764G>A, p.S255N)in the NMNAT1 gene which is responsible for causing LCA. Conclusion In this study, targeted exome sequencing revealed three variants in NMNAT1 that are likely to be the disease-causing variants of LCA. Key words: Optic atrophy, hereditary, Leber; Variants(genetics); Targeted exome sequencing; Leber congenital amaurosis; NMNAT1 gene