What is Krabbe disease?
Krabbe disease, which is also known as globoid cell leukodystrophy, is a rare inherited disorder that destroys the protective coating (myelin) of nerve cells in the brain and throughout the nervous system.
As a general rule, the younger the age of onset for Krabbe disease, the faster the disease progresses and the more fatal it is.
What causes Krabbe disease?
Krabbe disease occurs when a patient inherits two mutated copies of a gene that results in little or no production of an enzyme called galactocerebrosidase (GALC). These GALC enzymes are responsible for breaking down lysosomes in a cell’s recycling center. Since there is a short supply of these enzymes in Krabbe disease, a certain type of fat, known as galactolipids, build up in the body, in turn triggering myelin-forming cells to self-destruct. When this myelin is lost, nerve cells cannot send and receive their normal messages, causing severe complications in the body and the symptoms of Krabbe disease.
What are the symptoms of Krabbe disease?
In most cases of Krabbe disease, the signs and symptoms of the condition develop progressively in babies before six months of age, and it is common for death to occur by age 2. These symptoms early in the course of the disease include the following:
- Feeding difficulties
- Unexplained crying and extreme irritability
- Fever without a sign of infection
- Declines in alertness
- Delays in typical developmental milestones
- Muscle spasms or rigid, constricted muscles
- Loss of head control
- Frequent vomiting
Eventually, these symptoms can culminate into loss of developmental abilities, seizures, and an inability to swallow and/or breathe.
However, when the disease develops in older children and adults, the course can vary greatly. In these cases, symptoms also vary widely, but they may include:
- Progressive loss of vision
- Difficulty walking
- Decline in thinking skills
- Loss of manual dexterity
- Muscle weakness
How is Krabbe disease diagnosed?
After a healthcare provider conducts a thorough clinical examination and assesses the signs and symptoms that the patient is experiencing, he/she will base a diagnosis of Krabbe disease on a series of laboratory tests. These include the following:
- Blood sample and skin biopsy to assess GALC enzyme activity
- MRI and CT scans to detect the loss of myelin in the brain
- Nerve conduction study to assess the speed at which nerves conduct a signal
- Genetic testing
It is also worth noting that some states require a Krabbe disease screening test for newborns to measure GALC enzyme activity.
What are the available treatments for Krabbe disease?
If infants have already developed symptoms of Krabbe disease, there is currently no specific treatment that can change the course of the disease, so interventions focus on supportive care. These supportive interventions can include anticonvulsant medications to manage seizures, drugs to ease irritability, physical therapy, and nutritional support.
Recently, stem cell transplants have shown limited success in infants who are treated before the onset of symptoms and in some older children and adults. However, this type of therapy is risky and still being investigated.
Where can I find more information on Krabbe disease?