Riazuddin et al. (2010) studied 4 affected and 7 unaffected members of a large consanguineous Pakistani family segregating autosomal recessive retinitis pigmentosa (RP). Medical records of the 4 affected individuals were suggestive of early-onset RP, with diagnoses made ... Riazuddin et al. (2010) studied 4 affected and 7 unaffected members of a large consanguineous Pakistani family segregating autosomal recessive retinitis pigmentosa (RP). Medical records of the 4 affected individuals were suggestive of early-onset RP, with diagnoses made between 2 years and 4 years of age. Fundus photographs showed typical changes of RP, including attenuation of retinal arteries and bone spicule pigment deposits in the midperiphery of the retina. The diagnosis was confirmed by electroretinography (ERG), which showed typical RP changes with loss of both rod and cone responses in affected individuals but not in unaffected sibs or in the unaffected mother. None of the affected individuals had evidence of syndromic disease; specifically, there were no features consistent with Bardet-Biedl syndrome (BBS8; see 209900), which is also caused by TTC8 mutation. None had renal problems, and their body mass indices were within the normal range. There were no signs of polydactyly or midline defects or facies reminiscent of BBS, and no evidence of developmental delay, appreciable cognitive impairment, or inappropriate social behavior.
In a large consanguineous Pakistani family segregating autosomal recessive retinitis pigmentosa (RP) mapping to chromosome 14q, Riazuddin et al. (2010) sequenced candidate genes and identified a homozygous splice site mutation in the TTC8 gene (608132.0005) that segregated with ... In a large consanguineous Pakistani family segregating autosomal recessive retinitis pigmentosa (RP) mapping to chromosome 14q, Riazuddin et al. (2010) sequenced candidate genes and identified a homozygous splice site mutation in the TTC8 gene (608132.0005) that segregated with disease and was not found in 384 Pakistani control chromosomes or 384 chromosomes of northern European descent.