Variable expressivity in a Japanese family with autosomal dominant retinitis pigmentosa closely linked to chromosome 19q
M. Nakazawa, S. Xu, A. Gal, Y. Wada and M. Tamai
Department of Ophthalmology, Tohoku University School of Medicine, Sendai, Japan.
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.
