These are classified by the age of onset of symptoms. There is no way to predict what form an individual will develop. The type and progression of symptoms varies for each person who has the condition. If more than one person in a family is diagnosed with Krabbe disease, they may not have the same form or express the same symptoms. The different forms of Krabbe disease are allelic.
Symptoms usually start at three to six months of age.
Development may be normal up to that time. Children then have a more severe and rapid deterioration of mental and motor function. Eventually children lose mental and motor function, become deaf and blind, cannot move or speak, and typically must be fed through a tube. Death usually occurs within one year after symptoms appear. Juvenile Krabbe disease.