Substitutions of highly conserved amino acids in GJC2 (Cx47) cause LE in all four extremities [235], whereas loss-of-function mutations cause Hypomyelinating leukodystrophy 2 (OMIM 608804), in which LE does not occur. Here, GJC2 is linked to Pelizaeus-Merzbacher-like disease due to GJC2 mutation.