Mutations in GJA12 have been shown to cause Pelizaeus-Merzbacher-like disease (PMLD). We present two additional patients from one family carrying a homozygous frameshift mutation in GJA12. Both presented initially with nystagmus. The older girl developed ataxia first, then progressive spastic ataxia. The younger boy suffered from severe sensory neuropathy. Magnetic resonance imaging (MRI) of both children showed progressive demyelination in addition to dysmyelination, and also characteristic brainstem abnormalities. In children with nystagmus, ataxia and dysmyelination, mutation analysis of GJA12 should be considered early, especially if inheritance is autosomal recessive.