A new codon 15 rhodopsin gene mutation in autosomal dominant retinitis pigmentosa is associated with sectorial disease
L. J. Sullivan, G. S. Makris, P. Dickinson, L. E. Mulhall, S. Forrest, R. G. Cotton and M. S. Loughnan
Department of Ophthalmology, University of Melbourne, Australia.
OBJECTIVE: To ascertain and characterize rhodopsin gene mutations in
autosomal dominant retinitis pigmentosa and to correlate these mutations
with the clinical phenotypes. METHODS: DNA was extracted from leukocytes,
and the rhodopsin gene was amplified and analyzed using
molecular-biological methods. Clinical and electrophysiological data were
collected from patient charts. RESULTS: We found a disease-causing mutation
that was previously undescribed, to our knowledge, for autosomal dominant
retinitis pigmentosa within codon 15 of exon 1 of the rhodopsin gene. It
was a single base-pair transversion (AAT to AGT) leading to a
serine-for-asparagine substitution. This altered a glycosylation site in
the intradiscal portion of the rhodopsin molecule. The pedigree examined
demonstrated an inferior distribution of retinal pigmentary changes and
predominantly superior visual field loss with relative preservation of
electroretinographic amplitudes and good vision, which is consistent with
sectorial or sectorial-like retinitis pigmentosa. CONCLUSIONS: A codon 15
rhodopsin gene mutation caused retinitis pigmentosa in the pedigree
studied. There may be an association between intradiscal rhodopsin gene
mutations and sectorial forms of retinitis pigmentosa.
