RED-BLOOD-CELL FATTY-ACID LEVELS IN PATIENTS WITH AUTOSOMAL-DOMINANT RETINITIS-PIGMENTOSA

Fatty acid profiles were determined in red blood cell (RBC), plasma lipids and lipid fractions from 50 patients with autosomal dominant retinitis pigmentosa (ADRP) and 20 normal-sighted controls. In plasma of affected patients, significant increases in ω6 long-chain derivatives compared to controls resulted in elevated fatty acid unsaturation whereas, in RBCs, significant decreases in the levels of ω6 and ω3 long-chain polyunsaturates and a reduced unsaturation index were demonstrated (P < 0·01). The disproportionate levels of long-chain fatty acids in plasma vs. RBCs were consistent with abnormal function of acyl group transfer from plasma lipids to target tissues such as RBCs or, possibly, retina. Metabolic lipid anomalies were evaluated in two sub-groups of patients with ADRP; ten with the highest and ten with the lowest RBC lipid levels of the ω3 fatty acid, docosahexaenoic acid (DHA). Fatty acid product/precursor relationships in the sub-groups revealed reduced chain elongation and ω3 fatty acid desaturation associated with reduced ratios of rod-to-cone electroretinographic amplitudes. Based on these results, we suggest that the heterogenic ADRP population includes a sub-group of patients characterized by abnormal fatty acid metabolism that may effect membrane structure and visual function. © 1993 Academic Press. All rights reserved.