What Your Test Results Mean:

Carriers typically show no symptoms of Canavan disease; however, carriers are at an increased risk of having a child with Canavan disease. Risk for the current or future pregnancies is dependent on your partner’s carrier status.

Disease Explained:

Canavan disease is an inherited metabolic disorder in which harmful amounts of NAA accumulate within the central nervous system. Individuals with Canavan disease do not produce enough of one of the enzymes, aspartoacylase, needed to metabolize NAA. Over time, this excessive build-up of NAA in the brain causes demyelinization and other signs of the disease.

There are two forms of Canavan disease. In the most common form, infantile Canavan, normal development is followed by regression of developmental milestones within the first year of life. With time, sleep disturbance, seizures, and feeding difficulties become apparent. Life expectancy is variable ranging from several years of age to teens. Individuals with the more mild form, juvenile Canavan, will have abnormal MRI findings, and associated minor learning difficulties. Treatment of individuals with Canavan disease is supportive and directed to providing adequate nutrition and hydration, managing infectious diseases, and protecting the airway.

How the Genetics Works:

The clinical features of Canavan disease can be explained by pathogenic variants in the ASPA gene. In general, individuals have two copies of the ASPA gene. Carriers of Canavan disease have a single variant in one copy of the ASPA gene while individuals with Canavan disease have variants in both copies of their genes, one inherited from each parent.