Cromosome X-linked pigmentary retinosis

To report a clinical case of X-linked Retinitis pigmentosa, highlighting the importance of complementary studies and genetic testing, to the patient and his family, to identify the underlying mutation. A 10-year-old boy was brought to the clinic for refractive changes and difficulty seeing at night (nyctalopia). As a relevant family history, the maternal grandmother had Retinitis pigmentosa and the mother had high myopia (14.0 D). On ophthalmologic examination she had 4/10 corrected vision in both eyes, with moderate to severe myopia. Fundus examination showed diffuse mottled pigmentary changes with multiple yellowish-white dots distributed throughout the midperiphery, with arteriolar attenuation and mild bilateral optic nerve pallor. Autofluorescence showed a hyperautofluorescent ring around the macula and more peripheral hypoautofluorescence. On optical coherence tomography the ellipsoid zone is preserved centrally and these outer layers are thinned towards the periphery. The flash electroretinogram showed a dysfunction of both cones and rods that is not absolute. Regarding the genetic study, a variant in hemizygosis has been identified in the RPGR gene, being this result compatible with X-linked retinitis pigmentosa. In conclusion, it is of high relevance that those patients in whom we suspect a cone and rod dystrophy are extensively studied by a complete ophthalmologic examination, complementary studies, electrophysiologic and fundamentally genetic studies to identify the underlying mutation, since the advent of gene therapy could provide them with a better quality of life.