Are there earlier onset, later onset, or variant forms of Canavan disease?
The most common form of Canavan disease is the neonatal/infantile form. Infants begin to show symptoms between the first 3-5 months of life. Until that point, the child may appear to be normal. By 3-5 months, the child will not be meeting motor milestones, may have a large head (macrocephaly) and will not have control of their head because of weakened neck muscles (head lag).
A second form of Canavan disease is less common and is called the mild/juvenile form. People with this form of Canavan disease may experience problems with speech or movement starting in childhood. However, the problems may be so mild that they are never diagnosed as being caused by Canavan disease. An infant's head may be slightly enlarged, but the typical changes in the white matter of the brain (as seen on imaging tests) are absent.
Matalon, R, Michals-Matalon K. GeneReviews website. Updated August 11, 2011. Retrieved April 29, 2016, from http://www.ncbi.nlm.nih.gov/books/NBK1234/
Canavan disease. National Organization for Rare Disorders website. Updated 2015. Retrieved on May 1, 2016 from http://rarediseases.org/rare-diseases/canavan-disease/