Leukoencephalopathies are a group of medical conditions that primarily affect the white matter of the brain, which consists mainly of nerve fibers covered by myelin sheaths. These conditions are characterized by abnormalities in the structure and function of the white matter, leading to various neurological symptoms such as cognitive decline, motor impairment, seizures, and behavioral changes.

The term "leukoencephalopathy" is derived from two Greek words: "leukos," meaning white, and "enkephalos," meaning brain. The suffix "-pathy" refers to a disease or suffering. Therefore, leukoencephalopathies refer specifically to diseases that affect the white matter of the brain.

There are various types of leukoencephalopathies, including genetic, metabolic, infectious, toxic, and immune-mediated forms. Some examples include multiple sclerosis, adrenoleukodystrophy, Alexander disease, Canavan disease, and Marchiafava-Bignami disease. The diagnosis of leukoencephalopathies typically involves a combination of clinical evaluation, imaging studies such as MRI, and sometimes genetic or laboratory testing to identify the underlying cause. Treatment depends on the specific type and severity of the condition and may include medications, dietary modifications, physical therapy, or supportive care.