Description: Canavan disease (CD), which primarily affects children of eastern and central European Jewish (Ashkenazi) descent, is an inherited neurological disorder in which the brain deteriorates.
Symptoms: The signs of Canavan disease usually appear when the children are between 3 and 6 months of age. They include developmental delay (significant motor slowness), enlargement of the head, loss of muscle tone, poor head control, and severe feeding problems. As the disease progresses, seizures, shrinkage of the nerve to the eye and often blindness, heartburn (gastrointestinal reflux) and deterioration of swallowing develop. Most children with Canavan disease die in the first decade of life.
Cause: Canavan disease is caused by a deficiency of an enzyme called aspartoacylase (ASPA). This deficiency leads to the buildup of N-acetylaspartic acid (NAA) in the brain. The accumulated NAA causes a chemical imbalance that destroys myelin. Myelin, commonly known as the "white matter" in the brain, protects nerves and allow messages to be sent to and from the brain. When the chemical imbalance makes this "white matter" spongy, the incapacitating symptoms of Canavan's disease result.
Treatment: No effective treatment is available for Canavan's Disease yet.
Disease Frequency: 1 in 5,000 Ashkenazi Jews is affected by Canavan's Disease.
Carrier Frequency: 1 in 38 Ashkenazi Jews is a carrier of Canavan's Disease.
Diagnosis: The diagnosis of Canavan disease is made by detecting lack of enzyme aspartoacylase in skin cells or by genetic testing of the gene for Canavan disease in blood.
Screening: DNA testing can tell with over 95% certainty whether someone is a carrier of Canavan's Disease. Genetic counseling can assist at-risk couples in family planning. DNA-based prenatal testing, using samples obtained through CVS or amniocentesis, is available to couples who are both carriers.
History: The disorder was named for Myrtelle Canavan, the researcher who first described the disease in 1931.
Future: Because of the severity of Canavan Disease, the lack of treatment for it, and its high incidence in the Ashkenazi Jewish population, population screening within the Jewish community is beginning to be offered using the model developed for population screening for Tay-Sachs Disease.