Long-term strategies for the treatment of Refsum's disease using therapeutic apheresis

Refsum's disease is a rare autosomal recessive disorder of fatty acid metabolism. Poorly metabolized phytanic acid accumulates in fatty tissues, including myelin sheaths and internal organs, leading to retinitis pigmentosa, peripheral polyneuropathy, cerebellar ataxia, and renal, cardiac or liver impairment. Dietary restriction of phytanic acid in some cases is not sufficient to prevent acute attacks and stabilize the progressive course. Phytanic acid bound to large low density lipoproteins (LDL) and very low density lipoproteins (VLDL) molecules offers the possibility of extracorporeal elimination by lipid apheresis. We report on the long-term lipid apheresis treatment of four patients with severe Refsum's disease. Retinitis pigmentosa, peripheral polyneuropathy, cerebellar ataxia, anosmia, and sensorineural hearing loss were major symptoms exhibiting a progressive course. Lipid apheresis was performed for 5-13 years without severe complications. Maximum levels of phytanic acid before commencing chronic lipid apheresis were >300 mg/l. During steady state with lipid apheresis, mean phytanic acid before treatments was 87 mg/l and was reduced to 36 mg/l. Mean reduction rate was 59% per treatment. In all patients, abnormal motor nerve conduction velocity with signs of chronic denervation improved, morphological and functional stabilization of eye involvement was observed. Lipid apheresis prevented the extension of the disease to previously unaffected organs in three patients. Extracorporeal elimination of lipoprotein-phytanic acid complexes by lipid apheresis represents a pathophysiologically guided therapeutic approach, resulting in long-term improvement or stabilization of overall rehabilitation in patients with progressive Refsum's disease.