Krabbe disease refers to an inherited disorder that destroys the myelin, a protective coating of nerve cells inside the brain and throughout the nervous system. In most cases of this disease, the signs and symptoms develop in babies before the age of 6 months. This disease usually results in death by the age of 2 years. When it occurs in older children as well as adults, the disease’s course tends to vary greatly.
Causes
Krabbe disease is caused as a result of a person inheriting two copies of a mutated gene- one copy each is inherited from each parent. The gene provides a sort of blueprint for protein production. If there is a defect or error in the blueprint, the protein product is likely to not work the way it should. When a patient suffers from Krabbe disease, the two mutated copies of a certain gene result in little or no production of the enzyme, galactocerebrosidase (GALC).
This enzyme and such others are responsible for breaking down of certain substances in the cell’s recycling center, called lysosome. In this disease, the short supply of GALC enzymes leads to accumulation of certain types of fats that are called galactolipids.
Damage to the Nerve Cells
Galactolipids exist in cells that produce as well as maintain protective coating of the nerve cells. But, when there is an abundance of galactolipids, it causes a toxic effect. Some galactolipids may also trigger the cells that form myelin to self-destruct.
The other galactolipids get taken away by certain specialized debris-eating cells inside the nervous system that are called microglia. When the cleaning up process of excessive galactolipids begins, there is a transformation of helpful cells into toxic cells that are called globoid cells. These cells promote myelin-damaging inflammation.
The loss of myelin, called demyelization, prevents the nerve cells from transporting messages, both sending as well as receiving.
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