An electroretinographic and molecular genetic study of X-linked cone degeneration.
We evaluated full-field electroretinograms from members of a family with X-linked cone degeneration. The 15-year-old propositus had near normal visual acuity and a protan deficiency. His maternal grandfather and great uncle had a visual acuity of 20/200, a deficiency in color vision, and signs of macular degeneration; all had normal rod electroretinographic responses and diminished cone electroretinographic responses. The mother and maternal aunt of the propositus had normal visual acuity and diminished cone electroretinograms with predominant loss of red cone function. Their cone responses were greater than those of affected males. Genomic DNA isolated from these patients was analyzed with a red cone pigment gene cDNA probe that disclosed a 6.5-kilobase deletion in the red cone pigment gene. These findings substantiate that a defect in a gene encoding for a cone photoreceptor protein can lead to a cone photoreceptor degeneration.
Reichel
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E
Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston 02114.
Bruce
A M
AM
Sandberg
M A
MA
Berson
E L
EL
D000293:Adolescent; D000328:Adult; D000368:Aged; D015139:Blotting, Southern; D002872:Chromosome Deletion; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D004262:DNA Restriction Enzymes; D004596:Electroretinography; D005260:Female; D008040:Genetic Linkage; D006801:Humans; D008297:Male; D010375:Pedigree; D010786:Photoreceptor Cells / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D012162:Retinal Degeneration / Q000235:genetics* / Q000503:physiopathology; D012168:Retinal Pigments / Q000235:genetics; D014792:Visual Acuity; D014794:Visual Fields; D014960:X Chromosome
D015342:DNA Probes; D012168:Retinal Pigments; D004247:DNA; D004262:DNA Restriction Enzymes