Canavan Disease

Disease characteristics
Canavan disease is caused by mutations in ASPA gene, which provides codes for production of the enzyme aspartoacylase. This enzyme is responsible for the break down of a brain molecule called N-acetyl aspartate, which in concentrated forms interferes with the growth of myelin sheath in nerve cells. Lack of aspartoacylase enzyme activity causes malfunctioning of the myelin sheath, which is the fatty covering that surrounds nerve cells and acts as an insulator and allows for efficient transmission of nerve impulses.

Prevalence
Canavan disease could occur in any ethnic group, yet it affects persons of Eastern European Jewish ancestry more frequently. About 1/40 individuals of Eastern European (Ashkenazi) Jewish ancestry are carriers. Canavan disease is inherited in an autosomal recessive fashion.

Mutation
Two mutations account for approximately 97% of the Canavan disease cases in the Ashkenazi Jewish population. The most prevalent one is E285A with Y231Ter(X) occurring less frequently.

Testing criteria and symptoms
Being of Ashkenazi Jewish ancestry
Mental retardation, loss of previously acquired motor skills, abnormal muscle tone (floppiness)
Poor head control and megacephalus or abnormally enlarged head.