Recently, other hypomyelinating leukodystrophy genes such as TUBB4A and POLR3A have been shown to have distinct phenotypes and neuroimaging spectrum, ranging from spastic paraplegia to spastic ataxia without overt hypomyelination to hypomyelinating leukodystrophies resulting from different mutations 16, 17. This evidence concerns the gene POLR3A and spastic ataxia.