Variable expressivity in a Japanese family with autosomal dominant retinitis pigmentosa closely linked to chromosome 19q.

OBJECTIVE: To describe the clinical features of a Japanese family with autosomal dominant retinitis pigmentosa, the locus of which has been mapped on chromosome 19q.
DESIGN: Ophthalmologic testing, including visual acuity, slit-lamp biomicroscopy, and fundus examinations, for all family members examined. Selected members underwent kinetic visual field testing, electroretinography, and fluorescein angiography. PATIENTS: Eleven symptomatic members, two asymptomatic obligate carriers, and nine nonaffected members in four generations of a single family with autosomal dominant retinitis pigmentosa.
RESULTS: Asymptomatic carriers showed mildly affected fundus and fluorescein angiographic images. Visual field testing disclosed restricted central and midperipheral fields. Electroretinograms disclosed reduced amplitudes of rod-isolated responses in both of these family members, indicating functional abnormalities.
CONCLUSION: Marked variability in expressivity of the retinitis pigmentosa phenotype was found in a family with autosomal dominant retinitis pigmentosa linked to chromosome 19q.