Krabbe disease is an inherited disorder resulting in loss of myelin, a protective layer that forms around nerves, and neurologic degeneration. This is due to a deficiency of the enzyme galactosylceramidase. The classic form has onset in infancy. Babies with Krabbe disease appear normal at birth but become irritable and develop a stiff posture combined with developmental delay and feeding dificulties starting around 6 months. Their nervous system continues to deteriorate until they lose the ability to move, chew, swallow and breathe. They may also have seizures and lose their vision. Death usually occurs by about two years of age. Some people with Krabbe disease have a milder form with a highly variable onset between the ages of 1 and 50 years. These people may develop weakness, vision loss, and intellectual regression. Hematopoietic stem cell transplantation (HSCT) in presymptomatic infants or older individuals with milder symptoms has been able to improve or even preserve cognitive function but nervous system function may still deteriorate. Krabbe disease is caused by pathogenic variants in the GALC gene.