Krabbe disease is a rare inherited genetic degenerative disorder affecting the central nervous system. Symptoms of the disease begin in the first few months of life, usually before the age of 6 months. The incidence of its development in older children as well in adulthood is less, but not completely ruled out. According to an estimate, out of 100000 people, 1 person is affected by Krabbe disease in USA.
The disease is caused due to genetic mutation, leading to deficiency of an enzyme called Galactocerebrosidase (GALC). This enzyme is needed for growth and maintenance of myelin sheath.Myelin is a fatty insulation which covers the nerve fibers and helps in transmission of nerve impulses. Deficiency of this enzyme leads to breakdown of myelin coating resulting in destruction of brain cells.
Fretfulness, apathy, muscle weakness, difficulty in feeding, frequent episodes of fever, stiffness and later on blindness and hearing loss are some its symptoms. There is no definite cure for Krabbe disease. It is a fatal disease. Supportive treatment is given to ease patients suffering.
What Causes Krabbe Disease?
As mentioned above, Krabbe disease is an inherited genetic disease. There is deficiency of an enzyme called Galactocerebrosidase (GALC).It is an enzyme necessary for growth and maintenance of myelin sheath which insulates the nerve fibers of brain and spinal cord. Breakdown of myelin exposes the nerve fibers and leads to it destruction.
Physicians also refer to Krabbe disease as demyelinizing leukodystrophy. Here the primary metabolism of spingolipids is affected. Due to deficiency of GALC (which metabolizes lipids in the brain sheath), the galactolipids begin to accumulate, and they are responsible for the damage resulting in Krabbe disease.
Krabbe disease is produced when abnormal gene is inherited by the child from both mother and father. This pattern of genetic inheritance is called autosomal recessive. The gene located on chromosome 14 is responsible for causing the disease.
People from Israel (jews) are more commonly affected with this genetic disorder than other people.
Symptoms Of Krabbe Disease
Symptoms of Krabbe disease in early infancy:
- Irritability: the infant is restless and irritable and cries all the time.
- Feeding difficulties: he is unable to feed properly due to affection of involvement of muscles of swallowing.
- Muscle weakness.
- Child cannot keep his head straight. Head drops to one side.
- Unexplained fever without any sign of infection off and on.
- Stiffness and rigidity.
- Recurrent episodes of seizures.
- Slow and progressive loss of hearing and vision.
- Delay in mental and physical development.
In children who develop the disease later in life may present with complete blindness after progressive visual impairment. The child also has difficulty in walking, due to spasticity of muscles.
Krabbe Disease Treatment
There is no cure of Krabbe disease. Treatment is designed to ease the suffering of child. Treatment is purely symptomatic.
- Anticonvulsant medicines are given to treat seizures.
- Child is given medicines to relax muscle spasticity as well as to control irritability.
- Anti emetic medicines are given to reduce vomiting.
- Clinical trial is in its initial phase for umbilical cord blood stem cells and bone marrow transplantation to change or delay the course of disease.
- Physical therapy is beneficial for reducing muscle stiffness and deterioration of muscle action.
- Occupational therapy in elder children benefits to minimize dependence on others. It is aimed to prepare the child for performing his daily chores.
Infant suffering from Krabbe disease generally dies before the age of 2 years. Grown up children or adults who are suffering from Krabbe disease with relatively milder course may live for longer time.