ClinVar

In 11 affected members from 7 families with central areolar choroidal dystrophy (CACD2; 613105), Hoyng et al. (1996) identified heterozygosity for a 664C-T transition in exon 1 of the PRPH2 gene, resulting in an arg142-to-trp (R142W) substitution. The mutation was also detected in a 65-year-old female family member who had 20/20 visual acuity bilaterally and no posterior pole abnormalities on ophthalmoscopy or fluorescein angiography. The mutation was not found in 7 other unaffected family members or in 200 control chromosomes.

Boon et al. (2009) identified the R142W mutation in 98 patients with CACD from 45 different Dutch families and noted that 96 (98%) of the patients originated from the southeast region of the Netherlands. Analysis of CA repeat markers and SNPs near the PRPH2 gene in 3 large families carrying the R142W mutation revealed an approximately 519-kb shared chromosomal segment, strongly suggesting that R142W represents a founder mutation. Carrier frequency of R142W was analyzed in 57 asymptomatic controls over 70 years of age from the same region of the Netherlands; the mutation was found in a 76-year-old man who reported no visual disturbances, but who was found to have early stage II CACD on ophthalmoscopic examination and fundus autofluorescence imaging.