Identification of a novel RPGR mutation associated with X-linked cone-rod dystrophy in a Chinese family

Cone-rod dystrophy (CORD) is a group of inherited retinal dystrophies, characterized by decreased visual acuity, color vision defects, photophobia, and decreased sensitivity in the central visual field. Our study has identified a novel pathogenic variant associated with X-linked cone-rod dystrophy (XLCORD) in a Chinese family.

Our findings have expanded the spectrum of CORD-associated mutations in RPGR gene and serve as a basis for genetic diagnosis for X-linked CORD.

All six family members, including the proband, affected siblings, cousins and female carriers, have underwent thorough ophthalmic examinations. The whole exome sequencing was performed for the proband, followed by Sanger sequencing for spilt-sample validation. A mammalian expression vector (AAV-MCS) with mutated retinitis pigmentosa GTPase regulator (RPGR) sequence was expressed in HEK293 T cells. The mutated protein was verified by Western blotting and immunohistochemistry.

A novel mutation in the RPGR gene (c.2383G > T, p.E795X) is identified to be responsible for CORD pathogenesis. Conclusions: Our findings have expanded the spectrum of CORD-associated mutations in RPGR gene and serve as a basis for genetic diagnosis for X-linked CORD.