Expanding the Clinical Phenotypes of Peroxisome Biogenesis Disorders: PEX11 Function in Health and Disease

Pex11p and related proteins, collectively termed PPPs for Pex11p-type peroxisome proliferators, constitute an unusual group of proteins among the other Pex proteins. PPPs are genuine peroxisome proliferators, although they are not directly involved in matrix and membrane protein import. PPPs directly shape the peroxisomal membrane, but they also cooperate with fission proteins located at the peroxisome. Only recently, a relatively mild form of human peroxisome biogenesis disorder (PBD) associated with a defect in PEX11β could be identified. This finding provides new insight into the function of PPPs, expands the spectrum of clinical PBD phenotypes, and stresses the need for research into PBD pathophysiology and therapy.