Canavan Disease

Canavan disease is an inherited disorder that causes progressive damage to the nerve cells of the brain due to the deficiency of the enzyme aspartoacylase. Infantile Canavan disease is the more severe form, where symptoms occur at 3 to 5 months of age and include loss of motor skills, feeding and swallowing difficulties, abnormal muscle tone, and a poorly controlled and abnormally large head. Deafness, blindness, and paralysis can also occur. Life expectancy is variable, from within the first few years of life to their teens, depending on severity of symptoms manifested and medical management and care of symptoms. Children with the milder juvenile form may appear quite normal with only mild speech or developmental delay. They can survive into their teens and beyond. Currently, there is no standard treatment to lessen disease progression, but medical surveillance and care may help to improve some symptoms and overall condition of life. Canavan disease is caused by pathogenic variants in the ASPA gene.

Canavan disease is inherited in an autosomal recessive manner. This type of inheritance requires the presence of two copies of a pathogenic variant in the gene for a person to have the genetic disease. Both parents must be carriers of a pathogenic variant in the gene in order to be at risk to have an affected child. The child must inherit a pathogenic variant from each carrier parent in order to be affected. There is a 1 in 4 chance that a baby will inherit two mutated copies of the gene and be affected when both parents are carriers.

There are no signs or symptoms associated with being a carrier for Canavan disease. However, the risk to have a child affected with Canavan disease is increased. Testing of reproductive partners is recommended for carriers of Canavan disease.

Canavan disease affects all ethnicities but it is more common in the Ashkenazi Jewish. Canavan disease occurs in about 1 in 6400 to 1 in 3500 newborn babies in the Ashkenazi Jewish population.

Genetics Home Reference: Canavan disease (http://ghr.nlm.nih.gov/)
Canavan Foundation (http://www.canavanfoundation.org/)

OMIM [Canavan disease: 271900] (http://www.ncbi.nlm.nih.gov/omim)
Gene Reviews: Canavan disease

• Full gene sequencing