RPGR-Related X-Linked Retinitis Pigmentosa Carriers with a Severe "Male Pattern".

BACKGROUND: X-linked retinitis pigmentosa (XLRP) due to mutations in the RPGR gene is a very severe form of RP, resulting in rapid disease progression and retinal dysfunction. Female carriers do not usually report symptoms. However, it has reported that carriers of XLRP can have a significant visual and retinal impairment. OBJECTIVES: To report a detailed description of 3 cases of severely affected females who presented with a "male" phenotype and have posed challenges at diagnosis, due to the apparent autosomal dominant family history. METHOD: Autofluorescence imaging (AF), colour imaging and optical coherence tomography (OCT) were performed. Confirmation of the genetic mutation was obtained by Sanger genetic sequencing. In 1 patient an X-inactivation analysis was performed to detect the X-inactivation ratio, as the percentage of cells tested in which each allele is active. RESULTS: All the patients started suffering from night blindness in early childhood. Colour, fundus AF and OCT images showed the typical pattern of degeneration reported in men. One patient underwent retina implant surgery due to the severe atrophy. CONCLUSIONS: This is a small selection of females with a severe phenotype that do not differ from the typical male phenotype. In our opinion gene therapy surgery should be warranted in this scenario.