Molecular genetic and clinical evaluation of three Chinese families with X-linked ocular albinism

Xuan Zou,Hui Li,Ruifang Sui,Lizhu Yang,Huajin Li,Zixi Sun,Zhisheng Yuan

doi:10.1038/srep33713

Abstract

X-linked ocular albinism (OA1) is an X-linked inherited disease characterized by hypopigmentation of the fundus and nystagmus. Our study performed mutation analysis of the G protein-coupled receptor 143 gene (GPR143) and assessed the clinical characteristics of OA1 in three Chinese families. Three novel mutations, c.333_360+14del42insCTT, c.276G>A (p.W92X), and c.793C>T (p.R265X), were identified in GPR143 by PCR followed by Sanger sequencing in these families. All affected individuals presented with nystagmus, photophobia, poor visual acuity, foveal hypoplasia and varying degrees of hypopigmentation of the fundus. The fundus of female carriers showed pigmented streaks alternating with hypopigmented streaks. These results allowed us to expand the spectrum of mutations in GPR143 and phenotypes associated with ocular albinism.

Highlights

X-linked ocular albinism (OA1) is an X-linked inherited disease characterized by hypopigmentation of the fundus and nystagmus
All OA1 patients in this study presented with nystagmus, photophobia and poor visual acuity
We identified three novel, predicted loss of function (LOF) mutations in GPR143 among three patients with OA1

Summary

Introduction

X-linked ocular albinism (OA1) is an X-linked inherited disease characterized by hypopigmentation of the fundus and nystagmus. Our study performed mutation analysis of the G protein-coupled receptor 143 gene (GPR143) and assessed the clinical characteristics of OA1 in three Chinese families. The fundus of female carriers showed pigmented streaks alternating with hypopigmented streaks These results allowed us to expand the spectrum of mutations in GPR143 and phenotypes associated with ocular albinism. OA1 occurs almost exclusively in males, and results in only ocular abnormalities, including impaired visual acuity, nystagmus, photophobia, foveal hypoplasia, hypopigmentation of iris and fundus[1]. GPR143 encodes a protein that binds to heterotrimeric G proteins and is highly expressed in melanocytes and the retinal pigment epithelium (RPE)[2] It encodes a 404 amino acid protein predicted to be a membrane protein essential for development and maturation of melanosomes[3]. Our data expands the spectrum of phenotypes and mutations in the GPR143 gene in this population

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Results

Conclusion