Canavan Disease
What is Canavan disease?
Canavan disease is an inherited disorder that causes progressive damage to nerve cells in the brain. This disease is one of a group of genetic disorders called leukodystrophies. Leukodystrophies are characterised by degeneration of myelin, which is the fatty covering that insulates nerve fibers.
The signs and symptoms of this disease usually begin in early infancy; however, the course of the condition can be quite variable. Infants with Canavan disease typically appear normal for the first few months of life. By 3 to 5 months of age, affected infants begin having problems with development including a delay in motor skills such as turning over and sitting. These infants typically also have weak muscle tone (hypotonia), increased head size (macrocephaly), abnormal posture, and mental retardation. Feeding and swallowing difficulties, seizures, and sleep disturbances may also develop.
How common is Canavan disease?
This disorder occurs in 1 in 6,400 to 13,500 people of Ashkenazi (eastern and central European) Jewish heritage. Although it is more common in this population, the condition is seen in people of all ethnic backgrounds. The incidence in other populations is unknown.
What genes are related to Canavan disease?
Mutations in the ASPA gene cause Canavan disease.
The ASPA gene makes an enzyme called aspartoacylase. This enzyme normally breaks down a compound called N-acetyl-L-aspartic acid (NAA), which is predominantly found in nerve cells in the brain. Mutations in the ASPA gene prevent the breakdown of NAA, allowing this substance to accumulate to toxic levels in these cells. A buildup of NAA leads to the destruction of myelin, the covering that normally insulates and protects nerve cells. As a result, the exposed nerve fibers deteriorate, causing the serious signs and symptoms of Canavan disease.
How do people inherit Canavan disease?
This condition is inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.
What other names do people use for Canavan disease?
* ACY2 deficiency
* Aminoacylase 2 deficiency
* Aspa deficiency
* Aspartoacylase deficiency
* Asp deficiency
* Canavan-Van Bogaert-Bertrand disease
* Leukodystrophy, spongiform
* Spongy degeneration of central nervous system
* Spongy degeneration of the brain
* Spongy degeneration of white matter in infancy
* Van Bogaert-Bertrand syndrome
* Von Bogaert-Bertrand disease
