In mitochondria of different organs and blood cells isolated from Zellweger syndrome patients and PEX5 knockout mouse models, deformation of the cristae membrane was observed (Goldfischer et al, 1973; Baumgart et al, 2001), which may be related to the lack of plasmenylethanolamine despite the presence of a counterbalancing increase in the level of diacyl PE (Heymans et al, 1983). Here, PEX5 is linked to Zellweger syndrome.