Novel 615delC mutation in the CRX gene in a Japanese family with cone-rod dystrophy.

Abstract

To characterize the clinical features of a Japanese family with cone-rod dystrophy associated with a novel 615delC mutation in the cone-rod homeobox (CRX) gene. Case reports and results of DNA analysis. Mutational screening by direct sequencing was performed for the three exons in the CRX gene. The clinical features were evaluated by visual acuity measurements, electroretinography, and kinetic visual field testing. A 615delC mutation in the CRX gene was identified and found to cosegregate with cone-rod dystrophy. The ophthalmic findings included cone-rod dystrophy with negative-type electroretinograms (ERGs) and a rapid progression after the age of 40 years. These findings indicate that the 615delC mutation causes cone-rod dystrophy with a negative-type ERG. The genotype-phenotype correlation in the CRX gene in our patient and others reported in the literature suggest that the negative-type ERG might be a good sign for having a mutation in the CRX gene.