A serious inherited disease, most common amongst Ashkenazi Jews, which causes spongy brain degeneration. Symptoms appear soon after birth, and death very frequently occurs before the 18th month of life.

Symptoms may include:

Even if death does not occur in the infant stage, few sufferers live longer than 10 or 20 years.

Genetic councelling is reccomended for those with a family history of the disease, as it is caused when a child inherits a homozygous recessive trait, and can thus easily be avoided.