Canavan disease is a rare autosomal recessive leukodystrophy, which means both copies of the affected gene in each cell have mutations.
The parents of an individual with this disease usually each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. The affected gene is called ASPA, which provides instructions to make the enzyme aspartoacylase. This disease is more common in individuals with Ashkenazi Jewish ancestry, and most obstetricians recommend carrier testing for these individuals.
Diagnosis:
Age of onset is most commonly between 3 and 6 months. Although cases with later onset have been reported, they are extremely rare. Patients with early onset experience increasing difficulty in feeding, progressive lethargy, increasing stiffness of the limbs, and seizures. When the disease comes on later in infancy, children develop normal social, motor, and visual responses at first, but are lost as the disease advances. A prominent head lag and low muscle tone are present early in the course of the disease, followed by increased stiffness that begins in the legs and produces a posture of extension. Children typically develop a large head. Involvement of the optic nerve occurs in a large proportion of cases. Many patients die before the age of 10.
Treatment:
There is no cure for this disease. Canavan disease was the first leukodystrophy for which a gene therapy clinical trial was conducted. However, this approach is still under investigation. Drug trials, including Lithium and Acetate, are also under investigation.