Leukoencephalopathy with vanishing white matter syndrome (childhood ataxia with central nervous system hypomyelination/vanishing white matter disease) is an autosomal recessive disorder characterized by the occurrence of acute episodes of deterioration after minor head trauma or infection, and symmetrical demyelination on magnetic resonance with cavitation aspects. Mutations in each of the five subunits of eIF2B have been identified. We report in an affected man and his mother an adult-onset form of childhood ataxia with central nervous system hypomyelination/vanishing white matter disease-like disorder with no mutations in the EIF2B genes and normal guanine nucleotide exchange factor eIF2B activity, suggesting a new dominant inheritance of this syndrome that may involve other genes.