Chicago Center for Jewish Genetics Disorders - Ashkenazi Disorders: Canavan Disease

Ashkenazi Disorders: Mendelian

Gene: The gene responsible for Canavan disease is the aspartoacyclase (ASPA) gene, which is located at 17pter-p13. Aspartoacyclase hydrolyzes N-acetylaspartic acid (NAA) into aspartic acid and acetate. Its absence in the central nervous system leads to the accumulation of NAA in the brain resulting in demyelination and other symptoms seen in Canavan disease.

Mutations and testing: Four common mutations in the ASPA gene have been identified: E285A, Y231X, A305E, and 433-2A-->G. Testing for these four mutations leads to a detection rate of ~99% in Ashkenazi Jews for disease-causing alleles and ~50-55% in non-Ashkenazi Jews.

Traits: Canavan disease is a severe neurodegenerative disease (progressive leukodystrophy) with clinical onset usually by 3 to 6 months. Common features are hypotonia, poor head control, hyperextension of legs and flexion of arms, gastrointestinal reflux, feeding difficulties, severe mental deficiency, developmental delay, and macrocephaly. Over time, an affected child will develop spasticity, seizures, optic atrophy, and blindness. Death usually occurs within the first decade of life.

Treatment: There is no effective treatment for Canavan disease. Supportive care is aimed at providing the affected child with comfort.

Other: The American College of Obstetrics and Gynecology considers Canavan disease carrier screening to be standard of care for Ashkenazi Jewish couples. It should be offered to all couples in which one or both partners is of Ashkenazi Jewish descent who are pregnant or planning a pregnancy.

Later onset cases of Canavan disease have been described. Overall it is believed that most cases of Canavan disease are the "classical infantile" type but that progression of the disease is highly variable.

Canavan Disease from Geneclinics.org
http://www.genetests.org/profiles/canavan

Reviewed by Joel Charrow, MD, Head, Division of Genetics, Birth Defects and Metabolism, Children’s Memorial Hospital, 8/07

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This page last updated on September 7, 2007.