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 characterized 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 both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

Canavan Disease on Wikipedia

'''Canavan disease''', also known as '''Van Bogaert-Bertrand disease''' is a rare, inherited, neurological disorder characterized by spongy degeneration of the brain (in which the white matter is replaced by microscopic fluid-filled spaces). It was first described by Myrtelle Canavan in 1931. Canavan disease is one of a group of genetic disorders called the leukodystrophy that affect growth of the myelin sheath of the nerve fibers in the brain. Although Canavan disease may occur in any ethnic group, it affects persons of Eastern European Jewish ancestry more frequently. About 1/40 individuals of Eastern European (Ashkenazi) Jewish ancestry are carriers, about 1:10,000. Canavan disease is inherited in an autosomal recessive fashion. Both parents must be carriers in order to have an affected child. If both parents are carriers, there is a 25% chance to have an affected child. Genetic counseling and genetic testing is recommended for families who may be carriers. Canavan disease is caused by a defective ASPA gene, responsible for the production of the enzyme aspartoacylase. This enzyme breaks down the n-acetyl-asparate acid, which is a toxin. With decreased levels of aspartoacylase comes an increase in n-acetyl-aspartate, which interferes with growth of the myelin sheath of the nerve fibers in the brain. The myelin sheath is the fatty covering surrounding nerve cells that acts as an insulator, and allows for efficient transmission of nerve impulses. Symptoms of Canavan disease, which appear in early infant and progress rapidly, may include mental retardation, loss of previously acquired motor skills, feeding difficulties, abnormal muscle tone (i.e., floppiness or stiffness), poor head control, and megalocephaly ... [ Read More ]

External Resources

Molecular Genetics Testing Laboratory: Ashkenazi Jewish Genetic Disease Screen - Information about a test for seven common inherited diseases in the Ashkenazi Jewish population: Tay-Sachs disease, Canavan disease, cystic fibrosis, Gaucher disease, Bloom syndrome, familial dysautonomia and Fanconi anemia.

Family Village / Library / Leukodystrophy - Resources on Adrenoleukodystrophy, Alexander Disease, Canavan Disease, Krabbes Disease, Metachromatic Leukodystrophy, and Refsum's Disease.

Canavan Research Fund - The Canavan Research Fund is a not-for-profit organization dedicated to pioneering research that can treat and eventually cure Canavan and other genetic brain diseases.

Canavan Foundation - Not-for-profit foundation providing information about Canavan disease, prenatal screening, support, and research.

Canavan Research Illinois - Information about this organization as well as about the disease, its research, fund raising and contact details.

Canavan Disease - Information sheet compiled by NINDS, the National Institute of Neurological Disorders and Stroke.

Canavan Research Illinois - Information about this organization as well as about the neurological demyelinating disease, its research, fund raising and contact details.

Canavan Research Foundation - Not-for-profit organization dedicated to pioneering research that can treat and eventually cure Canavan and other genetic brain diseases.