ACBD5 and Peroxisome biogenesis disorder-Zellweger syndrome spectrum: Consequently, RDLKD is neither a peroxisomal biogenesis disorder nor single enzyme deficiency, since a deficiency in ACBD5 likely affects several aspects of peroxisomal function including VLCFA degradation, ether lipid synthesis, docosahexaenoic acid synthesis but also the transfer of membrane lipids from the ER to peroxisomes.