Krabbe disease is a rare, genetic, currently-incurable and ultimately fatal disorder. It is one of several known leukodystrophies: genetic diseases that progressively destroy the white matter of the brain.
In Krabbe disease, the enzyme galactocerebrosidase (GALC), which is essential for metabolizing several important compounds in the body, is deficient. Therefore, psychosine, a toxic substance which should be broken down and naturally released from the body starts to accumulate. This toxic build-up damages the central nervous system, particularly destroying the myelin sheath, which insulates the nerves. The destruction of the myelin sheath, called demyelination, impedes the conduction of nerve signals from the brain to the rest of the body. As the myelin degrades, it causes severe physical disabilities.