What is Canavan Disease?
Canavan disease is a rare, neurological disorder that causes deterioration of myelin (white matter) in the brain. This is a result of a gene mutation for the enzyme aspartoacylase, which in turn disrupts the production of myelin sheaths by oligodendrocytes (a type of brain cell). Myelin sheaths are, essentially, the fatty covering that insulate the nerve fibers in the brain and provide nutritional support for nerve cells. Without these, the nerve fibers are left vulnerable and are unable to properly function. This not only prevents nerve cells from properly sending and receiving messages, but it also causes the brain to degenerate into spongy tissue.
What are the Symptoms?
Symptoms progress rapidly, typically appearing within the first 3 to 6 months of life. These symptoms can include:
• Poor head control
• Abnormally large head
• Lack of motor development
• Hypotonia – decreased muscle tone (“floppiness” or weakness)
• Difficulty swallowing
• Feeding difficulties
• Hearing loss
• Sleep disturbances
How Do You Get Canavan Disease?
This disorder is inherited through an autosomal recessive pattern. This means that both of the parents are carriers of the Canavan gene, and that both of those genes were passed down to their offspring. This disorder can occur in people of any ethnic background who are carriers of the gene, but it is most common among the Ashkenazi Jewish population.
How is Canavan Disease Diagnosed?
There are multiple ways to screen for this disorder, including:
CT/MRI scans: These look for the deterioration of myelin, or white matter, in the brain.
Urine/blood/cerebrospinal fluid test: A fluids test will look for an increase in N-acetyl-L-aspartate (NAA), a molecule in the brain which can suggest low levels of aspartoacylase.
Genetic testing: This will test the child’s DNA for any sign of the aspartoacylase gene mutation.
Is There a Treatment?
Unfortunately, there is no cure. However, by screening early, the symptoms can be ameliorated in order to provide a better quality of life. For instance, physical therapy can improve posture and communication skills, and feeding tubes can ensure proper nutrition and hydration.