Canavan disease is an inherited neurological disease. It affects the myelin, or sheaths surrounding the nerves in the brain. It is one of a group of genetic neurological disease known as the leukodystrophies. These diseases each affect the production of a different chemical making up the myelin sheaths in the brain. Canavan disease affects the enzyme aspartoacylase.
The brain begins to degenerate after birth in Canavan disease, eventually becoming a spongy mass with fluid-filled pockets. Most infants are diagnosed at ages three to nine months. Canavan disease can usually be diagnosed by a blood test.
Canavan disease causes a range of neurological deficiencies, including mental retardation, blindness, paralysis, seizures and eventually, death. Sadly, most patients with Canavan disease do not live past age 10. It all depends on the speed of the disease's progression. Treatment is primarily supportive and seeks to keep the child comfortable.
Prenatal screening is available for Canavan Disease, named for Myrtelle Canavan, who described the disease in 1931. Persons of Ashkenazi Jewish descent are most often at risk, and it is estimated that 1 in 40 Ashkenazi Jews carries the gene for the disease. However, Saudi Arabians are also at a higher risk of carrying the gene. Both parents must be carriers for the gene to be passed on, and every child born to a couple where both parents are carriers has a 25 percent chance of having the disease.
Canavan disease has no cure now, but research is ongoing, particularly in the areas of stem cell and genetic research. Stem cells would help replace the faulty cells and would produce the necessary enzyme. Genetic research is focusing on transferring good copies of the gene via "viral vectors." The results are promising and some of the methods may also benefit others with degenerative neurological diseases such as Alzheimer's and Parkinson's disease. Patients who have undergone genetic therapy for Canavan disease have shown improvement, giving hope to their parents.
Most obstetricians will recommend their Jewish patients and their husbands to have a complete screening for all genetic diseases most prevalent in that population, particularly for Canavan disease and Tay-Sachs disease. Prospective parents are then better equipped to make decisions about their future families.
