Molecular characterization of retinitis pigmentosa in Saudi Arabia

Abstract

Purpose: To catalog mutations that underlie retinitis pigmentosa (RP) in Saudi Arabia using a representative sample.

Methods: Fifty-two patients with RP were recruited and their homozygosity mapping, with or without linkage analysis, was used to suggest the causative genes followed by bidirectional sequencing.

Results: Mutations were identified in 94% of our study cohort, including seven that were novel.

Conclusions: Homozygosity mapping is an extremely robust approach in the study of retinitis pigmentosa in the setting of high rates of consanguinity. BBS3 mutations can rarely present as nonsyndromic RP.

Figure 1

Summary of the novel mutations identified in this study. Simplified pedigrees are shown for each of the families (circle for female, square for male, white for unaffected, and black for affected). Below each pedigree, a sequence chromatogram is shown for the corresponding mutation, with a wildtype tracing for comparison (arrow indicates the position of the mutation on the chromatogram).

Figure 2

Analysis of the conservation level of the missense mutations identified in this study. For each missense mutation, a panel of orthologs from different organisms is shown to demonstrate the conservation of the involved residue across species, which suggests that a change of that residue may adversely affect the protein function.