Any retinitis pigmentosa in which the cause of the disease is a mutation in the HGSNAT gene.

Retinitis pigmentosa-78 (RP78) is an autosomal recessive retinal dystrophy that presents in the third to fourth decade with central visual disturbance, visual field defects, and nyctalopia. Fundus examination reveals optic disc pallor, attenuated retinal vessels, and irregular midperipheral intraretinal pigment migration (Arno et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of retinitis pigmentosa, see 268000.