Abstract
Abstract: :
Purpose: Danon’s disease (DD) is a rare X–linked condition characterized by cardiomyopathy, myopathy and various degrees of mental retardation and is the consequence of mutations in the gene encoding the lyzosome–associated membrane protein–2 (LAMP2). Diagnosis is usually made by muscle biopsy that shows characteristic autophagic vacuoles. These vacuoles are limited by a single membrane and contain cytoplasmic degradation products as well as glycogen. Methods: Two brothers from a Swiss family were diagnosed with DD and were clinically investigated because of decreased visual acuity. Complete eye examination was performed, including Humphrey perimetry, fluoresceine and indocyanine green angiography and photopic and scotopic ERG. Results: Inheritance of DD was clearly X–linked with no male–to–male transmission in the family. Mutation analysis of the LAMP2 gene revealed an S157X nonsense mutation. Best corrected vision was 0.8 and 0.6, respectively. Mid peripheral salt–and–pepper retina was noticed and visual field testing revealed a diffuse reduction of retinal sensitivity in both patients. ERG showed minimal dysfunction of both cones and rods in one of the brothers and of rod only in the other. Conclusions: Retinopathy is part of DD and further studies will tell whether this represents a frequent finding. A complete ophthalmic examination, including ERG should be performed in all patients and potential carriers. The retinopathy could be due to accumulation of autophagic vacuoles in various ocular tissues, in particular in the retinal pigment epithelium, followed by impaired function.
Keywords: genetics • retinitis • gene screening