PNPLA1 and paraplegia: Whereas ELOVL1 and ELOVL4 variants, which are responsible for elongation to ultra-long fatty acids, cause both skin (scaling) and neurologic abnormalities (paraplegia, ataxia, brain atrophy), CYP4F22, CERS3, and PNPLA1 (patatin-like phospholipase domain-containing 1) variants result in skin disease only, that is, excessive scaling of the skin.