Unlike the 5-base pair deletion STGD3-causing ELOVL4 mutation that results in expressing a truncated protein losing the ER retention/retrieval motif, all SCA34-causing ELOVL4 mutations are point mutations that result in expression of the full-length mutant ELOVL4 proteins possessing the essential ER retention/retrieval motif and histidine catalytic core that are crucial for VLC-FA biosynthesis (6). This evidence concerns the gene ELOVL4 and spinocerebellar ataxia type 34.