A hypomyelinating leukodystrophy characterized by infant or early childhood onset of delayed motor development and gait instability, followed by extrapyramidal movement disorders, progressive spastic tetraplegia, ataxia, hypomyelination, cerebellar atrophy, and atrophy or disappearance of the putamen that has_material_basis_in heterozygous mutation in the TUBB4A gene on chromosome 19p13.