In this review we will focus on the role of mutations in Cx47/GJC2 in several different phenotypes including a severe early onset dysmyelinating disorder, Pelizaeus-Merzbacher-like disease (PMLD1 or HLD2) [22], a milder, later onset disorder, hereditary spastic paraplegia (SPG44) [23], and a recently described subclinical leukodystrophy [24]. The gene discussed is GJC2; the disease is Pelizaeus-Merzbacher-like disease.