|Classification and external resources|
Alexander disease is a slowly progressing and fatal neurodegenerative disease. It is a very rare disorder which results from a genetic mutation and mostly affects infants and children, causing developmental delay and changes in physical characteristics.
Alexander disease is a genetic disorder affecting the central nervous system (midbrain and cerebellum). It is caused by mutations in the gene for glial fibrillary acidic protein (GFAP) that maps to chromosome 17q21. It is inherited in an autosomal dominant manner.
Alexander disease belongs to leukodystrophies, a group of diseases which affect growth or development of the myelin sheath. The destruction of white matter in the brain is accompanied by the formation of fibrous, eosinophilic deposits known as Rosenthal fibers.
The cause of Alexander disease is a mutation in the gene encoding glial fibrillary acidic protein.
Very rare. The infantile form (63% of all cases) starts usually at the age of six months or within the first two years. The average duration of the infantile form of the illness is usually about 3 years. Onset of the juvenile form (24% of all cases) presents usually between four to ten years of age. Duration of this form is in most cases about 8 years. In younger patients, seizures, megalencephaly, developmental delay, and spasticity are usually present. Neonatal onset is also reported. Onset in adults is least frequent. In older patients, bulbar or pseudobulbar symptoms and spasticity predominate. Symptoms of the adult form may also resemble multiple sclerosis.
There are no more than 500 cases reported.
There is currently no cure, or standard procedure taken for treatment.
The prognosis is generally poor. With early onset, death usually occurs within 10 years after the onset of symptoms. Usually, the later the disease occurs, the slower its course is.