The Epidermis in Refsum’s Disease (Heredopathia Atactica Polyneuritiformis)

Heredopathia atactica polyneuritiformis (HAP, Refsum’s Disease) comprises retinitis pigmentosa, peripheral polyneuropathy, cerebellar ataxia, deafness and ichthyosis as its major clinical components. It is extremely rare and shows an autosomal recessive mode of inheritance. It was first described by Refsum in 19461. There were no real advances in our understanding of the disease until 1963 when Klenk and Kahlke2 found high concentrations of an unusual branched chain C20 fatty acid (3,7,11,15-tetramethylhexadecanoic acid or phytanic acid) in renal and hepatic lipids and in the urine of an affected patient. This suggested a biochemical defect and subsequently phytanic acid in relatively large amounts was found in the blood of patients with Refsum’s disease3. (It occurs normally in human plasma in very low concentrations — 0.4–2 μg/ml representing less than 0.1% of total fatty acids4.)