Krabbe disease, also called globoid cell leukodystrophy (GCL), is a rare, inherited disorder that affects the central nervous system (CNS) and peripheral nervous system. People with Krabbe disease typically have increased muscle tone that causes muscle spasticity and stiffness, impaired motor control, vision problems, seizures, and hearing loss. In many cases, Krabbe disease leads to early death.
Krabbe disease is one of several disorders called leukodystrophies. Leukodystrophies are disorders that affect the growth of development of the myelin sheath, the fatty substance that insulates and protects the nerves in the brain and spinal cord. The myelin sheath continues to develop after birth, with the growth rate peaking before 18 months of age. The myelin sheath is completely developed when a person is about 20 years old. When the myelin sheath does not grow or function properly, it leads to nervous system damage.
People with Krabbe disease have deficient levels of the enzyme galactosylceramidase and as a result, galactolipids build up to toxic levels in the myelin. This causes oligodendrocytes, the cells that produce myelin, to die. Because the myelin is unable to function properly, the nerve cells in the brain and other parts of the body become damaged and destroyed and symptoms of Krabbe disease develop.
Although most people with Krabbe disease develop symptoms before the age of six months, some people may not have noticeable signs of the disease until childhood or adulthood. Based on when symptoms develop, the disease is divided into four major types. Type 1, or infantile Krabbe disease, begins when the infant is three to six months of age. An estimated 85-90% of Krabbe disease cases are classified as type 1. Type 2, or late infantile, typically begins when the baby is six months to three years of age. Type 3, or juvenile Krabbe disease, begins when the child is three to eight years of age. Type 4, or adult-onset Krabbe disease, develops anytime after the age of eight.
It is estimated that one out of 100,000 people worldwide have Krabbe disease. More reports have been documented in a few isolated communities in Israel, where the disease affects about six out of 1,000 people. This is because the disease is hereditary.
There is currently no cure for Krabbe disease. However, if a person undergoes genetic testing and is diagnosed with Krabbe disease before symptoms begin or if symptoms develop later in life, a bone marrow transplant or stem cell transplant may be an effective treatment. In most cases, treatment focuses on reducing symptoms of the disease. Type 1 generally leads to death before age two. Type 2 generally leads to death two years after symptoms develop. Infants who receive umbilical cord stem cells or bone marrow transplants in the early stages of the disease may have a better prognosis. People with types 3 and 4 typically experience milder symptoms and live much longer than infants with type 1 or 2.
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