11-26-2009, 11:37 AM
Canavan disease, also called Canavan-Van Bogaert-Bertrand disease, aspartoacylase deficiency or aminoacylase 2 deficiency,[1] is an autosomal recessive[2] degenerative 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 in the phospholipid layer insulating the axon of a neuron. The gene associated with the disorder is located on human chromosome 17.
Prevalence
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.
Pathophysiology
Canavan disease has an autosomal recessive pattern of inheritance.
Canavan disease is inherited in an autosomal recessive fashion. When both parents are carriers, there is a 25% chance of having an affected child. Genetic counseling and genetic testing is recommended for families with two parental carriers.
Canavan disease is caused by a defective ASPA gene which is responsible for the production of the enzyme aspartoacylase. This enzyme breaks down the concentrated brain molecule N-acetyl aspartate. Decreased aspartoacylase activity prevents the normal breakdown of N-acetyl aspartate, and the lack of breakdown somehow interferes with growth of the myelin sheath of the nerve fibers in the brain. The myelin sheath is the fatty covering that surrounds nerve cells and acts as an insulator, which allows for efficient transmission of nerve impulses.
Symptoms
Symptoms of Canavan disease, which appear in early infancy and progress rapidly, may include mental retardation, loss of previously acquired motor skills, feeding difficulties,loss of speach. abnormal muscle tone (i.e., floppiness or stiffness), poor head control, and megalocephaly (abnormally enlarged head). Paralysis,Seizures, blindness, even a vagatative state.and the loss of the ability to fight off illness. the Backflow of food material into the nose (nasal regurgitation),reflux with vomiting.
Treatment
There is no cure for Canavan disease, nor is there a standard course of treatment. Treatment is symptomatic and supportive.
Prognosis
Death usually occurs before 18 months but not most at age 4 . Some children may survive into their teens and a few into their twenties via newer gene therapy treatments which have extended their life expectancy. In some cases, this helps to temporarily stop the progression of the disease.
Leukodystrophies are characterized by degeneration of myelin in the phospholipid layer insulating the axon of a neuron. The gene associated with the disorder is located on human chromosome 17.
Prevalence
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.
Pathophysiology
Canavan disease has an autosomal recessive pattern of inheritance.
Canavan disease is inherited in an autosomal recessive fashion. When both parents are carriers, there is a 25% chance of having an affected child. Genetic counseling and genetic testing is recommended for families with two parental carriers.
Canavan disease is caused by a defective ASPA gene which is responsible for the production of the enzyme aspartoacylase. This enzyme breaks down the concentrated brain molecule N-acetyl aspartate. Decreased aspartoacylase activity prevents the normal breakdown of N-acetyl aspartate, and the lack of breakdown somehow interferes with growth of the myelin sheath of the nerve fibers in the brain. The myelin sheath is the fatty covering that surrounds nerve cells and acts as an insulator, which allows for efficient transmission of nerve impulses.
Symptoms
Symptoms of Canavan disease, which appear in early infancy and progress rapidly, may include mental retardation, loss of previously acquired motor skills, feeding difficulties,loss of speach. abnormal muscle tone (i.e., floppiness or stiffness), poor head control, and megalocephaly (abnormally enlarged head). Paralysis,Seizures, blindness, even a vagatative state.and the loss of the ability to fight off illness. the Backflow of food material into the nose (nasal regurgitation),reflux with vomiting.
Treatment
There is no cure for Canavan disease, nor is there a standard course of treatment. Treatment is symptomatic and supportive.
Prognosis
Death usually occurs before 18 months but not most at age 4 . Some children may survive into their teens and a few into their twenties via newer gene therapy treatments which have extended their life expectancy. In some cases, this helps to temporarily stop the progression of the disease.