Myelin proteolipid protein is the major myelin protein from the central nervous system (CNS). Myelin proteolipid protein probably plays an important role in the formation or maintenance of the multilamellar structure of myelin. In man point mutations in PLP are the cause of Pelizaeus-Merzbacher disease (PMD), a neurologic disorder of myelin metabolism. In animals dismyelinating diseases such as mouse 'jimpy' (jp), rat md, or dog 'shaking pup' are also caused by mutations in PLP. PLP is a highly conserved hydrophobic protein of 276 to 280 amino acids which seems to contain four transmembrane segments, two disulphide bonds and which covalently binds lipids (at least six palmitate groups in mammals). PLP is highly related to M6, a neuronal membran glycoprotein.