Potential Clinical Benefit of Very Long Chain Fatty Acid Supplementation in Spinocerebellar Ataxia Type 34

Spinocerebellar ataxia type 34 (SCA34) is a dominantly inherited disease that causes late-onset ataxia, in association with skin lesions in the form of erythrokeratodermia variabilis. It is caused by mutations in the ELOVL4 gene, which encodes for the ELOVL4 protein and has the function of lengthening very long chain (VLC) fatty acids (FA), which are important components of central myelin. The aim of this work was to review the medical literature on the biochemical abnormalities of SCA34, and based on the obtained information, to propose supplementation of deficient FAs. A review of the ad hoc medical literature was performed. Plasma levels of the ELOVL4 products C32, C34 and C36 FA have not been reported in SCA34 yet. However, pathogenic variants of ELOVL4 revealed deficient biosynthesis of C28, C30, C32, C34 and C36 FA compared to WT in cell cultures, and the levels of ceramides and phosphatidylcholines containing ≥ 34 C FA were decreased compared to WT in HeLa cells expressing mutant SCA34 proteins. Besides, a pathological study of SCA34 revealed myelin destruction and loss of oligodendrocytes in cerebral and cerebellar white matter. Levels of VLC-FA should be determined, to identify specifically deficient FAs in SCA34. Cerebellar ataxia could possibly be improved by administration of the deficient FAs, as found in SCA38 with supplementation of docosahexaenoic acid. The authors suggest investigators with access to SCA34, to take into consideration this therapeutic hypothesis, and try to verify the potential efficacy of administration of VLCFA in this disease.