In humans, Alexander disease is a rare type of leukodystrophy. This devastating childhood brain disorder develops due to abnormalities in the myelin sheath, a protective insulation that covers nerves. It often strikes infants before their first year of age and causes catastrophic damage throughout the nervous system. Most children do not survive past age 6. Mutations in GFAP gene (glial fibrillary acidic protein) are associated with nearly all cases of Alexander disease. 1 Affected individuals typically have progressive loss of developmental milestones, enlarged skull and frontal bossing, seizures, poor movement coordination, gradual loss of intellectual function, seizures, breathing problems and hydrocephalus.
Alexander disease is inherited in an autosomal dominant manner. The risk to inherit the disease depends upon the genetic status of the parents. If a parent is affected or has a mutation in the GFAP gene, the risk of inheriting the GFAP mutation is 50%. Diagnosis of Alexander disease is based on MRI findings. No specific therapy is currently available for this condition. Treatment is supportive and includes supportive care, antibiotic treatment for infection, antiepileptic drugs for seizure control, and assessment for learning disabilities and cognitive impairment. In dogs, this nervous system disease has been described in the Bernese Mountain Dog, Scottish Terrier and other breeds.2