Phenotypic progression in X-linked retinitis pigmentosa secondary to a novel mutation in the RPGR gene

Abstract

To report phenotypic progression for a novel mutation in the RPGRgene causing X-linked retinitis pigmentosa (RP), and describe the phenotype in affected males and females. Bidirectional fluorescent sequencing analysis was used to screen for mutations in RPGR. Five affected males and eight affected females from two English families underwent refraction, ETDRS visual acuity, OCT imaging, and Goldmann visual field testing. DNA analysis identified a novel c.350G>A sequence change in exon 5 of RPGR. The change segregated with disease in both families. For affected males there was a significant correlation between age and visual acuity (r=-0.91, P=0.034), and a non-significant correlation between age and visual field area (r=-0.56, P=0.4). For affected females, there was a significant correlation between age and visual acuity (r=-0.8, P=0.018), and between age and visual field area (r=-0.94, P=0.005). All affected females were highly myopic. No correlation between retinal thickness, and either age or sex was noted. This novel mutation in RPGRcauses X-Linked RP with complete penetrance in males and females. Affected females are highly myopic but retain better visual function than affected males. The phenotypic data can be used to provide a mutation-specific visual prognosis, and may also help recognition of the genotype.