Childhood ataxia with central nervous system hypomyelination / vanishing white matter (CACH/VWM) is characterized by ataxia, spasticity, and variable optic atrophy. The phenotypic range includes a prenatal/congenital form, a subacute infantile form (onset age <1 year), an early childhood-onset form (onset age 1 to <4 years), a late childhood-/juvenile-onset form (onset age 4 to <18 years), and an adult-onset form (onset =18 years). The prenatal/congenital form is characterized by severe encephalopathy. In the later-onset forms initial motor and intellectual development is normal or mildly delayed, followed by neurologic deterioration with a chronic progressive or subacute course. While in childhood-onset forms motor deterioration dominates, in adult-onset forms cognitive decline and personality changes dominate. Chronic progressive decline can be exacerbated by rapid deterioration during febrile illnesses or following head trauma or major surgical procedures, or by acute and extreme fright.

NDMSBA is an autosomal recessive neurodevelopmental disorder characterized by infantile onset of progressive microcephaly and spasticity and severe global developmental delay resulting in profound mental retardation and severely impaired or absent motor function. More variable features include seizures and optic atrophy. Brain imaging may show myelinating abnormalities and white matter lesions consistent with a leukoencephalopathy, as well as structural anomalies, including thin corpus callosum, gyral abnormalities, and cerebral or cerebellar atrophy. Some patients die in early childhood (summary by Falik Zaccai et al., 2017 and Hall et al., 2017).