Krabbe disease is an autosomal recessive leukodystrophy caused by a deficiency of galactosylceramidase, which is encoded by the GALC gene and is important for myelin turnover in the central and peripheral nervous systems. Krabbe disease has an infantile form, which is more common and phenotypically homogeneous, and a later-onset form, which is phenotypically heterogeneous.

In the infantile form, symptoms begin prior to 1 year of age after a period of normal early development. Early signs and symptoms of infantile Krabbe disease include irritability, hand fisting, and failure to thrive. A peripheral neuropathy may be present. Infants begin to regress developmentally and develop decorticate posturing with opisthotonus and sluggish pupillary reactions to light. The disease is relentlessly progressive, with development of blindness, deafness, and epilepsy, followed by death by 2 years.

In the later-onset form, symptoms begin after 1 year of age. The clinical course is more variable than that of the infantile form. However, symptoms typically occur between 1 and 3 years of age, after a period of normal development. Early signs and symptoms can include loss of developmental milestones, vision loss, gait changes, and seizures. The disease is more slowly progressive, and death typically occurs 4-6 years after symptom onset. In rare cases, symptom onset may not occur until later in childhood, adolescence, or adulthood.

Krabbe disease is rare, occurring in approximately 1:250 000 births in the United States. However, the incidence of disease varies among countries. For example, there is a high carrier rate in northern Israel and near Jerusalem.