Alexander disease is a rare autosomal dominant leukodystrophy, which means one copy of the altered affected gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene.
These cases occur in people with no history of the disorder in their family. Rarely, an affected person inherits the mutation from one affected parent. The gene involved in this disease is referred to as GFAP, glial fibrillary acidic protein.
The infantile form begins before age 2, and patients develop enlarged brain and head size, seizures, stiffness in the arms and/or legs, intellectual disability, and developmental delay. Less frequently, onset occurs later in childhood (the juvenile form) or in adulthood. Common problems in juvenile and adult forms of Alexander disease include speech abnormalities, swallowing difficulties, seizures, and poor coordination. Rarely, a neonatal form of Alexander disease occurs within the first month of life, and is associated with severe intellectual disability and developmental delay, accumulation of spinal fluid in the brain (hydrocephalus), and seizures.
There is no disease-specific treatment for this disorder, although several therapeutic targets are being evaluated in animal models.