What is Canavan disease?
Canavan disease is a rare genetic condition that damages the ability of nerve cells (neurons) in the brain to send and receive messages. People with this disorder lack an enzyme that is essential for the growth and maintenance of myelin. Myelin is a covering or "sheath" that coats, protects, and insulates nerve fibers. Collectively, myelin-covered nerve fibers are known as the white matter. Canavan disease can be separated into a severe infantile form and a milder juvenile form.
The infantile Canavan disease is the most common and most severe form of the condition. Affected infants appear normal for the first few months of life, but by age 3 to 5 months, problems with development become noticeable. These infants usually do not develop motor skills such as turning over, controlling head movement, and sitting without support. Other common features of this condition include weak muscle tone (hypotonia), an unusually large head size (macrocephaly), and irritability. Feeding and swallowing difficulties, seizures, and sleep disturbances may also develop. The juvenile form of Canavan disease is less common. Affected individuals have mildly delayed development of speech and motor skills starting in childhood. These delays may be so mild and nonspecific that they are never recognized as being caused by Canavan disease.
The life expectancy for people with Canavan disease varies. Most people with the neonatal/infantile form live only into childhood, although some survive into adolescence or beyond. People with the mild/juvenile form do not appear to have a shortened lifespan.
Canavan disease. Genetic Home Reference website. Updated April 26, 2016. Retrieved April 29, 2016, from http://ghr.nlm.nih.gov/condition/canavan-disease
Matalon R, Michals-Matalon K. GeneReviews website. Updated August 11, 2011. Retrieved April 29, 2016, from http://www.ncbi.nlm.nih.gov/books/NBK1234/