Alexander disease is a very rare autosomal dominant leukodystrophy, which are neurological conditions caused by anomalies in the myelin which protects nerve fibers in the brain. The most common type is the infantile form that usually begins during the first two years of life. Symptoms include mental and physical developmental delays, followed by the loss of developmental milestones, an abnormal increase in head size and seizures. The juvenile form of Alexander disease has an onset between the ages of 2 and 13 years. These children may have excessive vomiting, difficulty swallowing and speaking, poor coordination, and loss of motor control. Adult-onset forms of Alexander disease are less common. The symptoms sometimes mimic those of Parkinson’s disease or multiple sclerosis, or may present primarily as a psychiatric disorder.
According to the National Institute of Neurological Disorders and Stroke, the destruction of white matter is accompanied by the formation of Rosenthal fibers—abnormal clumps of protein that accumulate in astrocytes in the brain.
The disease occurs in both males and females, and no ethnic, racial, geographic or cultural/economic differences are seen in its distribution. Alexander disease is a progressive and often fatal disease.
Delays in development of some physical, psychological and behavioral skills; progressive enlargement of the head (macrocephaly), seizures, spasticity, and in some cases also hydrocephalus, idiopathic intracranial hypertension, and dementia.
In cases of early-onset or neonatal Alexander disease, symptoms include seizures, fluid buildup in the brain, high protein levels in cerebrospinal fluid, and severe motor and intellectual impairment. In cases of type I Alexander disease, where the condition appears before age 4, symptoms include seizures, enlarged brain and head, stiffness in the limbs, delayed intellectual and physical development, recurrent vomiting, and difficulties with gaining weight.