ALEXANDER DISEASE

What Is Alexander Disease?

Alexander disease is a rare, genetically determined degenerative disorder of the central nervous system. It is one of a group of disorders known as the leukodystrophies, diseases that result from imperfect growth or development of the myelin sheath, the fatty covering that acts as an insulator around nerve fibers in the brain. Myelin, which lends its color to the "white matter" of the brain, is a complex substance made up of at least 10 different chemicals. Each of the leukodystrophies affects one (and only one) of these substances. In Alexander disease, the destruction of white matter in the brain is accompanied by the formation of fibrous protein deposits called Rosenthal fibers. It is caused by mutations in the gene for glial fibrillary acidic protein (GFAP). The majority of cases are sporadic (not inherited), but there are families in which more than one child will have the disorder. Alexander disease primarily affects males and usually begins at about 6 months of age. Symptoms may include mental and physical retardation, dementia, enlargement of the brain and head, spasticity (stiffness of arms and/or legs) and seizures. In addition to the infantile form, juvenile and adult onset forms of the disorder have been reported. These forms occur less frequently and have a longer course of progression.

Is There Any Treatment?

There is no cure for Alexander disease, nor is there a standard course of treatment. Treatment of Alexander disease is symptomatic and supportive.

What Is the Prognosis?

The prognosis for individuals with Alexander disease is generally poor. Most children with the infantile form do not survive past the age of 6. Juvenile and adult onset forms of the disorder have a slower, lengthier course.

What Research Is Being Done?

The National Institute of Neurological Disorders and Stroke, a part of the National Institutes of Health, supports research on genetic disorders, including leukodystrophies such as Alexander disease. The goals of this research are to find ways to prevent, treat and, ultimately, cure these disorders.