Clinical Approach to Leukoencephalopathies

Deborah L.; Renaud, M.D.


Semin Neurol. 2012;32(1):29-33. 

In This Article

Abstract and Introduction


Recent advances in biochemical and molecular genetics have led to the discovery of new leukoencephalopathies. Despite these advances, many patients with leukoencephalopathy remain undiagnosed. A systematic approach to the investigation of these patients is needed to select the most appropriate testing strategy. In this article, the author presents a clinical and magnetic resonance imaging (MRI) based approach to the evaluation of patients with leukoencephalopathy.


Leukoencephalopathies are disorders that selectively involve the white matter of the brain. Acquired causes of leukoencephalopathy include inflammatory conditions, infections, vascular disorders, neoplasia, and toxic causes. Hereditary leukoencephalopathies encompass those conditions that demonstrate progressive destruction or loss of previously acquired myelin (leukodystrophies) as well as those conditions associated with impaired formation of myelin (dysmyelination or hypomyelination). The study of clinical features, neuroimaging patterns, and biochemical and neuropathologic features of leukoencephalopathies has led to the discovery of the genetic defects responsible for many of these conditions. Variations in phenotype-genotype correlation can make the prediction of the underlying condition challenging. Despite recent advances in molecular studies, ~50% of patients with hereditary leukoencephalopathies remain undiagnosed. A systematic approach to guide investigations is important to lead to a diagnosis.