Objective To assess the clinical and genetic characteristics of a Japanese family
with fundus albipunctatus with progressive cone dystrophy associated with
a mutation in the RDH5 gene.
Design Case report with clinical findings and results of fluorescein angiography,
electroretinograms, kinetic visual field testing, dark adaptometry, and DNA
analysis.
Setting University medical center.
Patients We studied the ocular findings in 6 members of a Japanese family with
fundus albipunctatus with cone dystrophy and a guanine-to-adenine transversion
at the first nucleotide in codon 35 of the RDH5 gene.
The mutation resulted in a substitution of serine for glycine in amino acid
35 (Gly35Ser) of the RDH5 gene.
Results Characteristic features included poor night vision, white dots in the
retina, cone dystrophy, and a mottled appearance of the retinal pigment epithelium.
Electroretinograms showed greater impairment of the rod-mediated responses
than the cone-mediated responses. After 3 hours of dark adaptation, the a
and b waves and scotopic b waves recovered.
Conclusions Although the mutation of the RDH5 gene has
been known as a causative gene of fundus albipunctatus, the Gly35Ser mutation
in the RDH5 gene may be related to the pathogenesis
of progressive retinal degeneration. This phenomenon may provide evidence
of gene phenotype caused by a mutation in the RDH5
gene.
Clinical Relevance The Gly35Ser mutation causes fundus albipunctatus with cone dystrophy.
This finding provides evidence that some kinds of mutations in the RDH5 gene are related, in part at least, to the pathogenesis of progressive
retinal degeneration.
