Krabbe disease is a rare nervous-system genetic disorder. It is a form of brain disease which is known as leukodystrophy. It is also known as leukodystrophy of globoid cells, or lipidosis of galactosylceramides.

CAUSES

Krabbe disease is caused by a mutation in the gene GALC. People with this gene deficiency will not make enough of the substance called beta-galactosidase (galactosylceramidase) galactocerebroside. The enzyme is required by the body to create myelin. Myelin surrounds and protects nerve fibres. Without this enzyme, myelin breaks down, brain cells die, and nerves inside the brain and other parts of the body do not function properly. Krabbe disease is inherited and is a recessive autosomal disorder. Krabbe disease can grow at different ages: In the first months of life, the early-onset disease appears. The majority of children with this type of illness die before they reach 2 years of age. Late-onset Krabbe disease starts in late infancy or early teenage years.

PATHOPHYSIOLOGY

Galactosylceramide is biosynthesized by ceramide galactosylation. It is highly concentrated in the sheath of myelin, where it is synthesized in oligodendroglia and cells like Schwann. The addition of a group of sulfates will convert galactosylceramide to sulfatide.

The composition of myelin in Krabbe disease isn’t qualitatively abnormal. The accumulation causes globoid cells to grow. Psychosine also accumulates and is thought to be a highly cytotoxic substance responsible for the widespread destruction of oligodendroglia which produces myelin. The rapid degradation of oligodendroglia leads to a breakdown of myelin, and further reduction of myelin production, causing the following symptoms.

SIGNS AND SYMPTOMS

  • Changing muscle tone from floppy to rigid
  • Hearing loss that leads to deafness
  • Failure to thrive
  • Feeding difficulties
  • Irritability and sensitivity to loud sounds
  • Severe seizures
  • Unexplained fevers
  • Vision loss that leads to blindness
  • Vomiting

COMPLICATIONS

  • Blindness
  • Deafness
  • Severe problems with muscle tone

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