Canavan Disease is a genetic disorder commonly found in Ashkenazi Jews. The disease causes a premature breakdown of white matter in the brain. The disease is associated with chromosome 17. Another name for Canavan Disease is Canavan-Van Bogaert-Bertrand disease. Myrtelle Canavan, for whom the disease was named, described the condition in 1931.
Who is at Risk?
The Ashkenazi Jewish population is particularly at risk for Canavan Disease, but it can cross ethnicities. About 1 out of 40 Ashkenazi Jews are carriers of the recessive trait. When two recessive carriers have children, each child has a 25% chance of contracting Canavan Disease. Alternatively, children have a 50% chance of being recessive carriers and a 25% chance of having no alteration of chromosome 17.
Symptoms
Parents may first notice the symptoms of Canavan Disease early in the developmental years. Common symptoms include:
- Mental developmental delays
- Loss of motor skills
- Difficulty feeding
- Floppy or stiff muscles
- Enlarged head
- Loss of sight
- Blindness
- Seizures
Complications
Canavan Disease is characterized by a breakdown of the white matter in the brain. Patients do not product the enzyme aspartoacylase. Aspartoacylase stops N-acetylaspartic acid from building in brain tissue. Without this enzyme, the acid builds and breaks down white matter. Patients may develop hyper-reflexive joints and optic tissue loss. As the disease progresses, patients may lose sight and the ability to walk. As the brain deteriorates, mental retardation may occur.
Diagnosis
Similar to other genetic disorders, the final diagnosis often occurs after genetic testing, but other tests may be used before genetic testing is suggested to rule out other conditions. Testing may include MRI, CT scan, blood tests and urine tests.
Prenatal testing of amniotic fluid can be used to diagnose Canavan Disease. If testing is positive, parents are often counseled on the details of the disease.
Treatment
There is no cure for Canavan Disease. Patients are treated to relieve the symptoms. Currently, lithium is being examined as a potential treatment for disease symptoms.
Life Expectancy
Infants born with Canavan Disease deteriorate quickly. In most cases, death occurs before two years of age. In rare cases, children may live to reach their teens or even early adulthood.
Prevention
Parents can undergo genetic testing for the recessive trait that causes Canavan Disease before having children. Genetic counseling is a good idea if one or both parents of Ashkenazi Jewish background.