Phenotypic high myopia in X-linked retinitis pigmentosa secondary to a novel mutation in the RPGR gene.

Background: Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous disease causing progressive degeneration of retinal photoreceptor cells. The most severe form of this disease is X-linked RP (XLRP), in which photoreceptor degeneration begins in early childhood and complete blindness often occurs by the fourth decade of life. Two genes commonly associated with XLRP have been previously identified.

Material And Methods: One Spanish family with confirmed XLRP was studied for mutations using direct sequencing. A genotype-phenotype correlation with pathologic myopia (PM) is detailed.

Results: A new pathogenic mutation in the third exon of the RP GTPase regulator (RPGR) was identified: a variant c212C>G (pSER71*). This mutation appears as a hemizygous variant in the male proband with RP, and as heterozygous variant in the females of this pedigree who invariably exhibit symmetrical PM in both eyes.

Conclusion: A complete family history allowed determination of the inheritance pattern providing genetic counseling for patients and their families. The geno-phenotypic attributes of this heterozygosity suggest a correlation between RP and PM. This novel mutation would expand the mutation spectrum of RP2 and RPGR, and help to study molecular pathogenesis of RP.