An inherited neurodegenerative disorder, Krabe disease is caused by a mutation in the GALC gene, which causes an enzyme deficiency called galactosylceramidase to fail to work properly in the brain and other parts of the body. As a result, nerve function is lost and various neurological problems develop. The fat accumulates and damages the protective coating of nerve cells, called myelin, resulting in loss of nerve function and various neurological disorders.
To develop Krabe disease, a person must inherit two copies of the mutated GALC gene from each parent, since the disease is autosomal recessive. A carrier is someone who has one copy of a mutated gene and does not experience symptoms of the disease, but he or she can pass on the gene to their children.
In Krabbe disease, the onset age and severity of the disease are affected by the mutation. The most common form is the infantile form, which affects about 90% of cases. The symptoms usually start between 1 and 7 months of age, and the disease progresses rapidly. Children with the infantile form usually die before the age of 2. The remaining 10% of cases have the late-onset form. In the late-onset form, symptoms can start at any age, from childhood to adulthood, and the disease progresses slowly.
The symptoms of Krabbe disease vary depending on the age of onset and the type of mutation in the GALC gene. However, some common symptoms include:
Irritability and crying
Feeding difficulties and weight loss
Fever and infections
Muscle weakness and stiffness
Loss of motor skills and developmental milestones
Seizures and spasms
Vision and hearing loss
Blindness and deafness
Mental deterioration and dementia
Paralysis and respiratory failure
The diagnosis of Krabbe disease is based on the medical history, physical examination, and various tests. Some of the tests that can help diagnose Krabbe disease are:
Blood tests: These can measure the level of the galactosylceramidase enzyme and the amount of certain fats in the blood. A low level of the enzyme and a high level of the fats indicate Krabbe disease.
Genetic tests: These can identify the mutation in the GALC gene and confirm the diagnosis of Krabbe disease. They can also be used for prenatal screening and carrier testing.
Nerve conduction studies: These can measure the speed and strength of the electrical signals in the nerves. A slow or weak signal indicates nerve damage and demyelination.
Magnetic resonance imaging (MRI): This can provide detailed images of the brain and the spinal cord. It can show the areas of the brain that are affected by Krabbe disease and the extent of the damage.
The treatment options for Krabbe disease are limited and mostly supportive. They aim to relieve symptoms, prevent complications, and improve the quality of life of the patient. Some of the treatment options include:
Acetaminophen, ibuprofen, anticonvulsants, and antibiotics can control pain, inflammation, seizures, and infections caused by Krabbe disease.
The purpose of physical therapy is to maintain the patient's muscle strength, flexibility, and function, as well as prevent contractures, which are permanent shortenings and tightenings of muscles and tendons.
The occupational therapist can help the patient with daily activities and routines, such as feeding, dressing, and bathing, as well as providing adaptive equipment, such as braces, splints, and wheelchairs.
A speech therapist can assist the patient with communication and swallowing issues associated with Krabbe disease, as well as provide alternative methods of communication, such as sign language, gestures, or devices.
Providing nutritional support can prevent malnutrition and dehydration. It can also provide special diets, supplements, or feeding tubes, depending on the patient's needs.
In addition to providing comfort and symptom management, palliative care helps patients and their families cope with the emotional, social, and spiritual aspects of Krabbe disease.
There is no way to prevent Krabbe disease, as it is a genetic disorder that is inherited from the parents. However, some steps that can be taken to reduce the risk or detect the disease early are:
Families who have children with Krabbe disease can benefit from genetic counseling by learning about the risks, options, and implications of the disease.
It is possible to detect the mutation in the GALC gene in the fetus during pregnancy with prenatal screening. It can be done by using techniques such as amniocentesis or chorionic villus sampling, which involve taking samples of fluid or tissue from the womb. Parents can use the results to make informed decisions about their child's care and pregnancy.
A blood spot test can be used to identify babies with Krabbe disease soon after birth. A blood spot test involves taking a small sample of blood from the baby's heel. Doctors can use the results to monitor the disease's progress and start treatment as soon as possible.
