Mutations of Krabbe Disease

Krabbe disease is an extremely rare genetic disorder that causes the destruction the nervous system. It generally affects infants, usually resulting in death before 2 years of age. The disease is caused by a genetic mutation and it has no known cure, although clinical treatments have been somewhat successful. About one in every 100,000 babies born in the United States is afflicted with this disease. Krabbe disease is caused by a genetic mutation. Both parents must be carriers of the mutated gene to pass it down to their children.

Genes

• Krabbe disease is a result of a mutation in the galactosylceramidase gene, which is located on chromosome 14. This gene helps in the production of an enzyme that uses water to break down galactolipids, a type of fat, found in the kidneys and, more importantly, the brain. This enzyme is also vital element in myelin, which is a coating that helps protect nerve cells that are fundamental to the proper function of the nervous system.

Mutation

• There are more than 70 mutations in the GALC gene that are known to cause Krabbe disease. One type of mutation is the addition of unwanted DNA, or base pairs, into the GALC gene. Others include deletion of base pairs entirely or the replacement of one base pair with a faulty base pair. One of the most common mutations is the deletion of a section of the GALC gene. Because of these mutations, the galactolipids that help to form myelin cannot break down correctly, leading to abnormal nerve and brain function.

Symptoms

• Infants who have inherited the genetic mutation that causes Krabbe disease do not typically display any symptoms for the first few months of life. However, before 6 months, infants with the disease will show rigidity in their bodies. A difficult temperament has been noted in cases of Krabbe's, as well as difficulty eating, seizures, fever, vomiting and underdeveloped motor functions. Although rare, Krabbe disease has also been known to affect adults. Symptoms can range from vision loss, total paralysis and the inability to think clearly.

Treatment

• Treatment for Krabbe disease is still a learning process. In cases of infantile GALC mutation or Krabbe disease, not much can be done except to make the baby as comfortable as possible, such as seizure medication and feeding tubes. However, treatment for some children not yet displaying symptoms of Krabbe's has shown to be somewhat successful. Bone marrow or stem cell transplants can be performed on children who have had a prenatal diagnosis of Krabbe disease. This can slow the effects of the disease, however these surgeries are not always successful.

Prognosis

• Krabbe disease is usually fatal before the age of 2 in most infants. In 1997, Buffalo Bills quarterback Jim Kelly and his wife had a son, Hunter, who was born with Krabbe disease. He died in 2005 at 8 years of age, and has been considered the longest living child diagnosed with infantile Krabbe disease. Children who develop Krabbe's also have a slim chance of survival, usually dying within a couple of years after diagnosis. Adult development of Krabbe's is also usually fatal, but people with the disease usually live about two to seven years after diagnosis.