Clinical Findings in an Autosomal Dominant Italian Family With Mutation in the RP1 Gene

Abstract

Abstract: : Purpose: To describe the clinical findings in a family with autosomal dominant retinitis pigmentosa (ADRP) and a mutation in the RP1 gene. Methods: 3 ADRP patients from a ADRP family underwent a complete ophthalmologic examination, including, best corrected visual acuity, Goldmann perimetry, fundus examination, retinography and electroretinography (ERG). All RP1 exons were PCR–amplified using published intragenic primers. The same primers were used for sequencing and the products were analysed on an ABI PRISM 377 DNA sequencer. Results: The mutation R677X detected in RP1 gene is a nonsense mutation. The 3 patients showed a late onset of disease after the third decade of life. The 79 years–old father show light perception, typical funduscopic signs of advanced stage of RP and extinguished ERG. The two sons, of 42 and 46 years of age, retained a good visual acuity (20/20) with fundus features ranging respectively from absence of retinal abnormalities and a myopic appearance. On Goldmann perimetry both patients showed a constricted visual field. The ERG, extinguished in the 46 years old patient, showed a rod cone pattern in the 42 years old brother. Conclusions: The clinical phenotype associated with the RP1 R677X mutation in our family is characterized by a late onset of RP. The advanced stage of disease arose by the age of 60 with diffuse retinal pigmentation and blindness. These findings support previous observations that nonpenetrance or minimal disease expression are typical features of the RP1 phenotype and should be taken in account for prognostic counselling in patients carrying RP1 mutation.

Keywords: retinitis • genetics • pathology: human