General Condition Information
- Globoid cell leukodystrophy (Krabbe disease)
- Krabbe leukodystrophy
What is Krabbe disease
Krabbe disease is an inherited (genetic) condition that prevents the body from recycling galactolipids. Krabbe disease is named for the first doctor to describe the condition.
Galactolipids are important for cells in the body to work properly, but when they can’t be recycled, they start to build up. High levels of galactolipids destroy the protective covering of nerve cells called myelin.
The enzyme galactosylceramidase (GALC) breaks down galactolipids to help provide energy. This process takes place in lysosomes, the recycling compartments in your cells.
Krabbe disease develops when GALC enzyme activity decreases. This makes it harder for lysosomes to break down galactolipids. Two galactolipids, galactosylceramide and psychosine, build up. This buildup destroys myelin and prevents nerve signals from traveling throughout the body. This damage leads to the signs and symptoms of the condition.
There are two types of Krabbe disease that differ in signs and symptoms and age of onset:
- Early infantile Krabbe disease
- Later-onset Krabbe disease
It is not yet fully known why a person develops one type of Krabbe disease over the other.
Newborn Screening and Follow-Up
Newborn screening for Krabbe disease requires collecting a small amount of blood from your baby’s heel. To learn more about this process, visit the Blood Spot Screening page.
Screening measures how much GALC enzyme is in your baby’s blood. Babies with a low level of this enzyme might have Krabbe disease.
In some cases, screening measures how much of the galactolipid psychosine is in your baby’s blood. Babies with a high level of psychosine might have Krabbe disease.
Screening may also look at the gene that causes Krabbe disease. Babies found to have changes in the Krabbe disease gene may have Krabbe disease.
If your baby’s blood spot screening result for Krabbe disease is out-of-range, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.
An out-of-range screening result does not mean that your baby definitely has the condition. It does mean that your baby needs more follow-up testing. To learn more about screening results, visit the Blood Spot Screening Results page.
Your baby may need the following tests after an out-of-range screening result:
- Blood or urine tests
- DNA testing using a blood or cheek swab sample
- Measurement of certain proteins in the spinal fluid (a CSF total protein test)
- Magnetic resonance imaging (MRI)
- Tests of your baby's nerve function (nerve conduction velocity test)
You should complete any recommended follow-up testing as soon as possible. Babies with this condition can have serious health problems soon after birth if they are not diagnosed and treated quickly.
False-positive newborn screening results for this condition may happen. Some babies with positive newborn screening results for Krabbe disease have “pseudodeficiency.” Pseudodeficiency means that a baby’s enzyme levels are low on the screening but are normal in their body. These babies do not have and will never develop Krabbe disease. In very rare cases, babies may have positive newborn screening result for Krabbe disease, but actually have a different disease called Saposin A deficiency.
Newborn screening helps babies lead healthier lives. If your baby has an out-of-range result, follow up with your health care provider quickly. It is important to follow their instructions. Your baby may need to get treatment right away, even if they are not showing signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.
Signs of Krabbe disease can appear in the first few months after birth, particularly in the early infantile-onset form. The later-onset form of Krabbe disease may not appear until later in infancy, childhood, adolescence, or adulthood.
Signs of the condition may include the following:
A change in the GALC gene causes this condition. This gene gives instructions for making the GALC enzyme that breaks down glycolipids including galactosylceramide and psychosine.
A changed GALC gene prevents the cells from breaking down glycolipids properly. When these glycolipids are not broken down, they can become toxic and cause the breakdown of myelin. When myelin is destroyed, nerve cells are no longer protected and they are unable to send important nerve signals throughout the body.
- Krabbe disease is an autosomal recessive condition. Babies inherit the condition when each parent passes down a nonworking GALC gene to their baby. Only babies with two nonworking GALC genes—one from the mom and one from the dad—have this condition.
- People with one working copy and one nonworking copy of the GALC gene are called carriers.
- Carriers do not have or develop the condition. However, they may pass down a nonworking copy of the gene to their children.
- If two parents are carriers of a nonworking copy of the GALC gene, they have a 1 in 4 chance of having a child with Krabbe disease.
- Carriers for Krabbe disease often do not know they are carriers before having a child with the condition. In most cases, families have no history of the condition until the birth of a child with Krabbe disease.
- Parents who already have a child with Krabbe disease still have a 1 in 4 chance of having another child with Krabbe disease. This 1 in 4 chance stays the same for all future children.
- Genetic counselors and medical geneticists can help families learn about this condition and the chance of having children with it. Visit the National Society of Genetic Counselors to find a genetic counselor and the American College of Medical Genetics and Genomics to find a medical geneticist.
Treatment and Management
It is important to talk to your health care provider about which treatment(s) are best for your baby. The goal of treatment is to try to address the health problems caused by this condition.
Treatments may include the following:
- Stem cell transplant (SCT)
- Specific treatments to address health problems like:
- Feeding problems
- Respiratory problems
Children who receive early and ongoing treatment for Krabbe disease may live longer and have fewer health issues.