Krabbe disease is caused by a genetic defect that results in a deficiency in an enzyme called galactocerebrosidase (GALC). This enzyme is essential for the maintenance of myelin — a fatty substance that insulates your nerve fibers.

Doctors sometimes refer to Krabbe disease as globoid cell leukodystrophy. Globoid cells store molecules called galactolipids. Without GALC, galactolipids accumulate in the brain. Psychosine is a type of galactolipid, and it's the one suspected of causing the most damage in Krabbe disease. The damage occurs because when psychosine levels are high, the cells that produce myelin begin to self-destruct.

A child needs to inherit an abnormal gene from each parent to trigger the disorder. This inheritance pattern is called autosomal recessive. The gene for Krabbe disease is located on chromosome 14.

Jun. 11, 2011