Bareil et al. (2001) identified a consanguineous French family in which typical and severe retinitis pigmentosa segregated as an autosomal recessive trait in 3 affected individuals. The proband had night blindness since early childhood. Later, she experienced loss ... Bareil et al. (2001) identified a consanguineous French family in which typical and severe retinitis pigmentosa segregated as an autosomal recessive trait in 3 affected individuals. The proband had night blindness since early childhood. Later, she experienced loss in the peripheral visual field. At 30 years of age, the fundus showed typical bone spicule-shaped pigmentary deposits. Visual fields were reduced to 10 degrees in both eyes. Electroretinograms exhibited no rod response, whereas cone responses were severely reduced. Kondo et al. (2004) identified an individual with autosomal recessive retinitis pigmentosa (RP45) carrying a homozygous mutation in the CNGB1 gene (600724.0002; see MOLECULAR GENETICS). The patient was a 67-year-old Japanese man who had noticed night blindness at school age. He was diagnosed with retinitis pigmentosa at the age of 30 because of visual field defects. Twenty-five years later, after bilateral cataract surgery, dark-adapted flash electroretinograms were nonrecordable in both eyes. A fundus examination revealed a typical bony spicule pigment lesion and nonremarkable macular changes in the left eye, whereas the degeneration involved the macula in the right eye.
In affected individuals from a consanguineous French family with retinitis pigmentosa, Bareil et al. (2001) found homozygosity for a missense mutation in exon 30 of the CNGB1 gene (G993V; 600724.0001). The G993V mutation occurs in one of the ... In affected individuals from a consanguineous French family with retinitis pigmentosa, Bareil et al. (2001) found homozygosity for a missense mutation in exon 30 of the CNGB1 gene (G993V; 600724.0001). The G993V mutation occurs in one of the 3 invariant glycines in the CNGB1 cyclic nucleotide-binding domain, and was predicted to affect binding of cGMP to CNGB1. In a screen of 59 patients with autosomal recessive retinitis pigmentosa, Kondo et al. (2004) found 1 individual with a homozygous splice site mutation in the CNGB1 gene (600724.0002). The mutation resulted in frameshift and truncation of the protein, with loss of the last 28 amino acids.