Novel mutation in SCO2 of patients with high myopia from Enshi Tujia and Miao Autonomous Prefecture of China

Abstract:

AIM: To evaluate the pathogenic variants of the SCO2(OMIM 604272)gene in patients with high myopia from Enshi Tujia and Miao Autonomous Prefecture of China.METHODS: A total of 384 patients with high myopia whose spherical refractive error was ≤ -6.00 D and whose axial length was ≥26.00 mm in at least one eye were recruited. DNA was extracted by the phenol-chloroform method from 5 mL of peripheral venous blood. Sanger sequencing was performed to identify pathogenic variants in exon 2 of SCO2. The detected variants were evaluated via in silico prediction software. A total of 288 people from the same district were included as the normal control cohort.RESULTS: Seven variants were detected, namely, four synonymous variants(c.201C>T/p.=, c.576C>T/p.=, c.633A>C/p.=, c.780T>C/p.=.), two missense variants(c.187A>G/p.Ile63Val, c.59G>C/p.Arg20Pro)and one nonsense variant(c.544C>T/p.Gln182*). The two missense variants were not damaging, as predicted by PolyPhen2, SIFT and Provean. The novel nonsense variant(c.544C>T/p.Gln182*)cannot be found in the 1000 Genomes Project and was not identified in 288 normal controls. Variant Taster suggested that the nonsense variant site was conserved.CONCLUSION: The newly identified nonsense mutation may be responsible for high myopia of the patients in our cohort. SCO2 is associated with high myopia, while the incidence of SCO2 variants in high myopia in this cohort was as low as 1/384; the nonsense mutation may be a scarce variant of high myopia in the Enshi Tujia and Miao Autonomous Prefecture of China.

Key words:high myopia; SCO2; Sanger sequencing; mutation; nonsense mutation