In decreasing order of frequency, 3 forms of Alexander disease are recognized, based on age of onset: infantile, juvenile, and adult. Younger patients typically present with seizures, megalencephaly, developmental delay, and spasticity. In older patients, bulbar or pseudobulbar symptoms predominate, frequently accompanied by spasticity. The disease is progressive, with most patients dying within 10 years of onset. Imaging studies of the brain typically show cerebral white matter abnormalities, preferentially affecting the frontal region. All 3 forms have been shown to be caused by mutations in the GFAP gene.
Confirmation of a clinical diagnosis, Carrier testing in unaffected family members