Humbert et al. (2006) studied a 24-year-old Moroccan patient with typical fundus albipunctatus, born of first-cousin parents. He carried a 7.36-kb homozygous deletion encompassing the last 3 exons of RLBP1 (7, 8, and 9) and part of the intergenic region between RLBP1 and ABHD2, which lies downstream of RLBP1. This deletion abolished the retinal binding site of CRALBP. The telomeric breakpoint of the deletion (in RLBP1 intron 6) is embedded in an Alu element, whereas the centromeric breakpoint (in the intergenic region) lies between two Alu elements placed in the opposite orientation.

Dessalces et al. (2013) performed clinical and molecular investigations in patients with retinitis punctata albescens (RPA) at various ages, from November 2003, through June 2012, with no planned patient follow-up. The study included 11 patients with RPA (mean age, 24 [range, 3-39] years) from seven families and 11 control subjects undergoing evaluation. All patients had night blindness (before age 6 years in 10). Screening for mutations in the RLBP1 gene uncovered two novel mutations (p.Tyr111X and p.Arg9Cys). Eight patients from Morocco were homozygous for the recurrent 7.36-kilobase RLBP1 deletion of exons 7 through 9.

Katsanis et al. (2001) performed direct sequencing for the RLBP1 and RDH5 genes in four consanguineous Saudi families affected with retinitis punctata albescens. A homozygous p.R150Q missense mutation was identified in the RLBP1 gene in one of the families, affecting a highly conserved residue in the protein and probably resulting in a slowly progressive disease. Other genes were tested for the affected patients including: RHO, RDS, ABCR, TIMP3 and EFEMP1. None of these genes were associated with the disease in the three Saudi families.