Primary leukodystrophies

The term leukodystrophy reflects diseases that are both progressive and genetically determined arising from a gene defect that manages production or metabolism of exclusively one component of myelin. These defects cause imperfect growth, development or maintenance of myelin sheaths. The magnetic resonance imaging and spectroscopic features of six primary leukodystrophies are described and illustrated in this review. This includes Alexander disease, Canavan's disease, Childhood ataxia with central nervous system hypomyelination, Leukoencephalopathy with brain-stem and spinal cord involvement and elevated white matter lactate, Megalencephalic leukoencephalopathy with subcortical cysts, and Pelizaeus-Merzbacher disease.