Purchase this article with an account.
M. Nakamura, K. Lin, H. Terasaki, Y. Miyake; Novel GRM6 Mutations and Clinical Phenotype in Japanese Patients With Complete Congenital Stationary Night Blindness . Invest. Ophthalmol. Vis. Sci. 2006;47(13):4626.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The complete type of congenital stationary night blindness (CSNB) is a subtype of Schubert–Bornschein type of CSNB, in which the fundus is essentially normal. In patients with complete CSNB the rod function is absent, and the ON response is affected electrophysiologically. The hereditary pattern is X–linked recessive or autosomal recessive, and the causative gene for X–linked recessive complete CSNB is the leucine–rich proteoglycan nyctalopin gene (NYX). Recently the GRM6 gene encoding the glutamate receptor mGluR6 was identified as the mutated gene in autosomal recessive complete CSNB (PNAS. 2005). The aim of this study is to report mutations of the GRM6 gene in Japanese patients with complete CSNB and to describe the clinical features in the patients.
Five patients from 5 separate Japanese families with complete CSNB without NYX gene mutation were examined. Genomic DNA was extracted from leukocytes of the peripheral blood, and all 10 exons of the GRM6 gene were amplified by polymerase chain reaction and directly sequenced. A complete ophthalmologic examination was performed including best–corrected visual acuity, slit–lamp and fundus examination, fundus photography, and electroretinography.
A mutation in the GRM6 gene was identified in 2 patients. One had a novel homozygous E387A mutation and the other had a novel compound heterozygous mutation of D183N and c.232_234del. Several polymorphisms was identified. The clinical and electrophysiological features in both patients were consistent with those of complete CSNB, and were similar to those in patients with NYX mutation or to those without any mutation in either gene.
We have identified 3 novel mutations in the GRM6 gene in 2 Japanese families with complete CSNB. These results confirmed that some Japanese patients with complete CSNB are caused by a GRM6 gene mutation.
This PDF is available to Subscribers Only