is a degenerative disorder that affects the nervous system. It is caused by the shortage (deficiency) of an enzyme called galactosylceramidase (GALC). This enzyme deficiency results in defective myelin, the covering that insulates many nerves. Krabbe disease is considered part of a group of disorders known as leukodystrophies, which result from the imperfect growth and development of myelin. Krabbe disease usually begins before the age of 1 year (early-onset form). Initial signs and symptoms often include feeding difficulties, episodes of unexplained fever, stiff posture, and developmental delay. As the disease progresses, muscles continue to weaken, affecting the infant's ability to move, chew, swallow, and breathe. Affected infants also experience vision loss and intellectual disability. Less commonly, onset can occur later in childhood, adolescence, or adulthood (late-onset form). Krabbe disease is caused by mutations in the GALC gene and is inherited in an autosomal recessive pattern. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.