Collin et al. (2008) examined 6 affected individuals from 3 families with retinitis pigmentosa, all but 1 of whom displayed characteristic RP abnormalities including night blindness as the initial symptom, retinal bone-spicule pigmentation and attenuated retinal vessels, constriction ... Collin et al. (2008) examined 6 affected individuals from 3 families with retinitis pigmentosa, all but 1 of whom displayed characteristic RP abnormalities including night blindness as the initial symptom, retinal bone-spicule pigmentation and attenuated retinal vessels, constriction of visual fields, and a nonrecordable ERG or ERG responses in a rod-cone pattern. Two unrelated patients had posterior subcapsular cataracts. The authors observed differences in the photoreceptor dystrophy between the families: in 1 patient from family A, the cones were more severely affected than the rods (cone-rod pattern) and kinetic visual fields were not constricted but showed bilateral central scotomas; fundus examination revealed central abnormalities at the level of the retinal pigment epithelium and moderate attenuation of retinal vessels. Her 60-year-old brother also had central fundus lesions, but his ERG showed neither rod nor cone activity. Family B had relatively late onset of a classic form of RP, with preservation of central vision. The proband in family C, who was the youngest patient in the study, was the only one who was legally blind, due to severely constricted visual fields.
By direct sequence analysis in 7 Spanish autosomal recessive RP families, Abd El-Aziz et al. (2008) excluded 60 of the approximately 110 genes within the RP25 interval. To investigate whether copy number variation (CNV) exists within RP25, comparative ... By direct sequence analysis in 7 Spanish autosomal recessive RP families, Abd El-Aziz et al. (2008) excluded 60 of the approximately 110 genes within the RP25 interval. To investigate whether copy number variation (CNV) exists within RP25, comparative genomic hybridization (CGH) analysis was performed on the consanguineous RP5 family, revealing the presence of a 100-kb deletion in all affected family members that further narrowed the RP25 critical region. Abd El-Aziz et al. (2008) analyzed 6 predicted genes within the RP25 interval on chromosome 6q12 in 10 Spanish RP families previously linked to the RP25 interval and identified homozygosity or compound heterozygosity for 6 different mutations in a gene they designated EYS (612424). Mutations consisting of 4 deletions and 2 nonsense substitutions (e.g., 612424.0001-612424.0004) led to premature stop codons in 5 unrelated families. Collin et al. (2008) independently identified the EYS gene and analyzed it in 10 probands with autosomal recessive retinitis pigmentosa, revealing homozygosity for a nonsense mutation (Y3156X; 612424.0005) and a 1-bp deletion (612424.0006) in 2 patients. They subsequently identified the Y3156X mutation in another proband from a group of 131 unrelated RP patients, and haplotype analysis suggested a founder effect. The mutations were absent or present in heterozygosity in unaffected family members.