A novel IMPDH1 mutation (Arg231Pro) in a family with a severe form of autosomal dominant retinitis pigmentosa

Purpose: To define ophthalmic findings in a family with autosomal dominant retinitis pigmentosa and a novel IMPDH1 gene mutation. Design: Genetic and observational family study. Participants: Sixteen affected members of a family with autosomal dominant retinitis pigmentosa. Methods: Ophthalmic examination, including best-corrected visual acuity (VA), slit-lamp biomicroscopy, direct and indirect ophthalmoscopy, Goldmann kinetic perimetry, and electroretinography were performed. Deoxyribonucleic acid single-strand conformation polymorphism (SSCP) analysis was done. Abnormal polymerase chain reaction products identified by SSCP analysis were sequenced bidirectionally. Results: All affected patients had the onset of night blindness within the first decade of life. Ocular findings were characterized by diffuse retinal pigmentary degenerative changes, marked restriction of peripheral visual fields, severe loss of VA, nondetectable electroretinography amplitudes, and a high frequency of posterior subcapsular lens opacities. Affected members were observed to harbor a novel IMPDH1 gene mutation. Conclusion: A novel IMPDH1 gene mutation (Arg231Pro) was associated with a severe form of autosomal dominant retinitis pigmentosa. Families affected with a severe form of this genetic subtype should be investigated for a mutation in the IMPDH1 gene. (C) 2004 by the American Academy of Ophthalmology.