Abstract
Abstract: :
Purpose: To report the gene mutation and clinical findings in a family with X-linked recessive cone-rod dystrophy. Methods: Three generations of larger pedigree with an X-linked recessive retinal dystrophy were investigated with DNA mutational analysis, standard clinical examinations, pedigree analysis, photography, electroretinography, and kinetic visual fields over a twenty year period. Results: A mutation in exon 8 of the RPGR was found in this family. The male members of the family have subnormal visual acuities in the range of 20/60 to 20/100 from infancy which remains stable through adulthood, and nystagmus by age two was commonly found in males. The fundus examination of affected males and carriers is normal with no retinal changes, which is confirmed also on fluorescein angiography. The electroretingram shows a negative waveform in the bright flash dark adapted ERG, while the photopic ERG is barely to nondetectible by single flash testing, and the rod isolated ERG is nondetectible to 30% of normal. Female carriers have normal ERGs. Despite the severe findings on the ERG, the Goldmann visual fields are relatively full in all affected male patients. Conclusions: These patients with RPGR mutations clinically have the phenotype of incomplete congenital stationary night blindness, but the genetic etiology is different from previous report of the CACNA1F calcium channel gene, which has been identified with this phenotype. This dystrophy, while presenting with nystagmus and subnormal vision, appears to be nonprogressive and mild in affected in males.
Keywords: retinal degenerations: hereditary • retina • electroretinography: clinical