Management of hereditary retinal degenerations: Present status and future directions

Research on hereditary retinal degenerations has considerably improved our understanding of these disorders, although much remains to be learned about the exact mechanism involved in the pathogenesis. The advent of recombinan t DNA technology will refine diagnostic capabilities, which have so far bee n based on the manifestations of the disease to localization of the molecul ar defects. The correlation of the molecular defects with the phenotype of the disease will result in better prognostic counseling for patients. In ce rtain forms of retinitis pigmentosa, such as Refsum disease, gyrate atrophy of the choroid and retina, and abetalipoproteinemia, exact biochemical def ects have been identified and specific treatments have been applied with so me success. In other forms of retinitis pigmentosa, various investigations have suggested the possibilities of arresting the progress of degeneration by means such as the use of growth factors and controlling apoptosis. Effor ts to alter the expression of the mutated gene or to introduce a normal gen e into the genome are in their infancy, but results are encouraging. Vitami n A has been tried in patients with retinitis pigmentosa, and the results d emonstrate statistically significant beneficial effects of this vitamin, su ggesting that the course of the disease can be decelerated to some extent. Another interesting research area with potential for therapeutic applicatio n is the replacement of the retinal pigment epithelium or the degenerated n eural retina by transplantation of the respective cell types. Clinical tria ls are being conducted both with retinal pigment epithelium and neuroretina l transplants. (Surv Ophthalmol 43:427-444, 1999. (C) 1999 by Elsevier Scie nce Inc. All rights reserved.).