Purchase this article with an account.
P. F. Kenna, V. Collins, P. Humphries, G. J. Farrar, S. Millington-Ward; A Distinctive Phenotype in Autosomal Dominant Retinitis Pigmentosa Due to a Gln184Pro Rhodopsin Mutation. Invest. Ophthalmol. Vis. Sci. 2010;51(13):1378.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To describe the distinctive phenotype found in an autosomal dominant form of Retinitis Pigmentosa (RP) due to a Gln184Pro rhodopsin gene mutation.
A 29 year old male was referred for investigation of night blindness. Significantly, his 56 year old mother and 89 year old maternal grandfather had previously been diagnosed as suffering from RP. Full-field electroretinography was carried out on the proband and his mother. The unusual conformation of the electroretinogram suggested the possibility of a rhodopsin gene mutation as causative of the retinopathy. Rhodopsin gene sequencing was performed on DNAs from the propositus, his affected mother, his unaffected father, his unaffected sister and his affected maternal grandfather.
The proband and his mother reported long-standing symptoms of night blindness. Neither reported significant problems with day-vision. Full field electroretinograms (ERG) revealed non-recordable rod-isolated responses in both individuals. The proband’s dark-adapted mixed rod/cone response to the maximal intensity flash revealed an electronegative conformation with relative preservation of the a wave and almost total collapse of the b wave. The proband’s cone ERG responses to both single flash and 30Hz flicker were normal for timing and amplitudes. His mother also had an electronegative maximal response similar to her son’s, albeit of lower amplitude. Her cone responses were significantly delayed and reduced in amplitudes. Fundoscopy of the proband revealed essentially normal retinal features while his mother showed classical RP changes. The proband’s ERG responses were highly reminiscent of those seen in a form of autosomal dominant Congenital Stationary Night Blindness (CSNB) previously found by our group to be due to a Thr94Ile rhodopsin mutation. Sequencing of rhodopsin in the proband, his mother, his unaffected father, his unaffected sister and his affected maternal grandfather revealed a previously reported A>C substitution at nucleotide 3683 in exon 2 resulting in a Gln184Pro amino acid change segregating with the disease.
The hitherto unreported phenotype of Gln184Pro linked RP is marked by a very distinctive electronegative ERG response. This feature has been described in a number of inherited retinal disorders including CSNB, X-linked retinoschisis as well as Retinitis Pigmentosa. The occurrence of this unusual ERG finding in the context of autosomal dominant RP may indicate the possibility of a rhodopsin gene mutation.
This PDF is available to Subscribers Only