PEX7 and Peroxisome biogenesis disorder-Zellweger syndrome spectrum: Rhizomelic chondrodysplasia punctata type 1 (RCDP1) is a distinct peroxisome biogenesis disorder caused by defects in PEX7 that impair the peroxisomal pathways of plasmalogen (Pls) synthesis and phytanic acid (PA) oxidation.