NIGHT BLINDNESS IN SORSBYS-FUNDUS-DYSTROPHY REVERSED BY VITAMIN-A

Sorsby's fundus dystrophy (SFD) is an autosomal dominant retinal degen eration caused by mutations in the tissue inhibitor of metalloproteina ses-3 (TIMP3) gene, Mechanisms of the visual loss in SFD, however, rem ain unknown. In a SFD family with a novel TIMP3 point mutation, we tes ted a hypothesis that their night blindness is due to a chronic depriv ation of vitamin A at the level of the photoreceptors caused by a thic kened membrane barrier between the photoreceptor layer and its blood s upply. Vitamin A at 50,000 IU/d was administered orally. Within a week , the night blindness disappeared in patients at early stages of disea se. Nutritional night blindness is thus part of the pathophysiology of this genetic disease and vitamin A supplementation can lead to dramat ic restoration of photoreceptor function.