Abstract
Purpose:
The ocular albinism type I (OA1) is easily misdiagnosed as congenital idiopathic nystagmus in some Chinese patients with OA1. In this study, we described the clinical features and identify the disease-causing genes for five Chinese families with X-linked congenital nystagmus.
Methods:
Five families with X-linked congenital nystagmus were recruited and patients underwent ophthalmological examinations. Blood samples were collected and DNA was extracted. Two candidate genes of the G-protein coupled receptor 143 (GPR143) gene and the FERM domain-containing 7 gene (FRMD7) were directly sequenced and mutations analyzed. OCT were performed to analyze the macular structure.
Results:
Mutations in GPR143 gene were detected in each of the five families, including a nonsense mutation of c.333G>A (p.W111X), two splicing mutations of c.360+1G>C and c.659-1G>A, a small deletion mutation of c.43_50dupGACGCAGC (p.L20PfsX25), and a previously reported missense mutation of c.703G>A (p.E235K). OCT examination showed foveal hypoplasia in all affected patients with nystagmus.
Conclusions:
Four novel mutations and one known mutation were identified in five Chinese families with OA1. These mutations will expand the mutation spectrum of GPR143 gene and contribute to the study of the GPR143 gene’s molecular pathogenesis. Molecular diagnosis and optical coherence tomography (OCT) are two useful tools for differentiation diagnosis.