Globoid-cell leukodystrophy (GLD), or Krabbe disease (pronounced crab-AY), is an inherited disorder. An inherited disorder means that the disease is caused by faulty genes passed on from parents to children. Genes are instructions that tell the body how to make all the different substances the body needs to work properly.
In GLD, the body is missing an important enzyme. Enzymes are types of proteins that break down different kinds of substances in the body. When the body is missing certain enzymes, the cells don't work properly. In GLD, the body is missing an enzyme called galactocerebrosidase needed to break down several types of fat-based compounds in the body. Without the enzyme, the compounds build up in cells throughout the body.
This build-up damages the myelin sheath, which is a substance that surrounds nerve cells. The myelin sheath works like insulation on a wire, and without it, nerves in the brain and elsewhere cannot work properly. The signals they send to each other fade out or get sent to the wrong place.
Patients with GLD have difficulty with memory, learning, speaking, understanding, and other mental functions. Movement is also affected. Patients with GLD have poor muscle control, muscle weakness, and stiff joints. Without treatment, this damage gets worse over time and there is no treatment that can undo any damage that has already happened.
GLD is very rare. Only about 40 children are diagnosed in the United States each year. The damaging symptoms most often show in the first months of life (early-onset). There is also a less common form of the disease that doesn’t show until later in childhood or even into teenage years (late-onset).