A NEW CODON 15 RHODOPSIN GENE MUTATION IN AUTOSOMAL-DOMINANT RETINITIS-PIGMENTOSA IS ASSOCIATED WITH SECTORIAL DISEASE

Objective: To ascertain and characterize rhodopsin gene mutations in a utosomal dominant retinitis pigmentosa and to correlate these mutation s with the clinical phenotypes. Methods: DNA was extracted from leukoc ytes, and the rhodopsin gene was amplified and analyzed using molecula r-biological methods. Clinical and electrophysiological data were coll ected from patient charts. Results: We found a disease-causing mutatio n that was previously undescribed, to our knowledge, for autosomal dom inant retinitis pigmentosa within codon 15 of exon 1 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 ex amined demonstrated an inferior distribution of retinal pigmentary cha nges and predominantly superior visual field loss with relative preser vation of electroretinographic amplitudes and good vision, which is co nsistent with sectorial or sectorial-like retinitis pigmentosa. Conclu sions: A codon 15 rhodopsin gene mutation caused retinitis pigmentosa in the pedigree studied. There may be an association between intradisc al rhodopsin gene mutations and sectorial forms of retinitis pigmentos a.