All are feature of Refsum disease except:
Ans: b. Defect in p oxidation Refsum disease is a rare autosomal recessive disorder caused by a deficiency of a-hydroxylase" (Lippincott 4th/195)"Refsum's disease: Alpha oxidation does not occur. Alpha oxidation is mainly used for fatty acids that have a methyl group at beta-carbon, which block beta-oxidation. This process occur mainly in endoplasmic reticulum & some also in peroxisomes.Refsum's disease is a rare neurologic disorder due to a metabolic defect that results in the accumulation of phytanic acid, which is found in dairy products and ruminant fat and meat. Phytanic acid is thought to have pathological effects on membrane function, protein prenylation, and gene expression" (Harper 30th/231, 28th/191)Refsum disease can manifest in infancy to early adulthood with the classic tetrad of (1) peripheral neuropathy, (2) retinitis pigmentosa, (3) cerebellar ataxia, and (4) elevated CSF protein concentration .Refsum disease is genetically heterogeneous but autosomal recessive in nature. Classical Refsum disease with childhood or early adult onset is caused by mutations in the gene that encodes for phytanoyl-CoA a-hydroxylase (PAHX).Refsum disease is treated by removing phytanic precursors (phytols: fish oils, dairy products, and ruminant fats) from the diet.
Deficiency of a-hydroxylase
Defect in p oxidation
Accumulation of phytanic acid
Peripheral neuropathy