To ascertain and characterize rhodopsin gene mutations in autosomal dominant retinitis pigmentosa and to correlate these mutations with the clinical phenotypes.
DNA was extracted from leukocytes, and the rhodopsin gene was amplified and analyzed using molecular-biological methods. Clinical and electrophysiological data were collected from patient charts.
We found a disease-causing mutation that was previously undescribed, to our knowledge, for autosomal dominant retinitis pigmentosa within codon 15 of exon l of the rhodopsin gene. It was a single base-pair transversion (AAT to AGT) leading to a serine-for-asparagine substitution. This altered a glycosylation site in the intradiscal portion of the rhodopsin molecule. The pedigree examined demonstrated an inferior distribution of retinal pigmentary changes and predominantly superior visual field loss with relative preservation of electroretinographic amplitudes and good vision, which is consistent with sectorial or sectorial-like retinitis pigmentosa.
A codon 15 rhodopsin gene mutation caused retinitis pigmentosa in the pedigree studied. There may be an association between intradiscal rhodopsin gene mutations and sectorial forms of retinitis pigmentosa.