pediatrics
Peroxisomal Disorders
Introduction
Peroxisomes are intracellular organelles that contain enzymes for beta-oxidation. These enzymes overlap in function with those in mitochondria, with the exception that mitochondria lack enzymes to metabolize very long-chain fatty acids (VLCFA), those 20 to 26 carbons in length. Therefore, peroxisomal disorders generally manifest with elevated VLCFA levels (except rhizomelic chondrodysplasia and Refsum disease). Although VLCFA levels may help screen for these disorders, other assays are also required (eg, plasma levels of phytanic, pristanic, and pipecolic acids; red blood cell plasmalogen levels). For information on other disorders affecting fatty acid metabolism, see Overview of Fatty Acid and Glycerol Metabolism Disorders . See also There are 2 types of peroxisomal disorders: Those with defective peroxisome formation Those with defects in single peroxisomal enzymes X-linked adrenoleukodystrophy is the most common peroxisomal disorder (incidence 1/17,000 births); all others are For more information, see the Peroxisome Biogenesis and Very Long-Chain Fatty Acid Metabolism Disorders . 