Krabbes&; disease is due to deficiency of
**Core Concept**
Krabbe's disease is a rare, genetic disorder that affects the nervous system, characterized by a deficiency of a specific enzyme involved in the breakdown and remodelling of myelin, the fatty substance that surrounds and protects nerve fibers.
**Why the Correct Answer is Right**
Krabbe's disease is caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is responsible for breaking down galactosylceramide, a key component of myelin. The lack of GALC leads to the accumulation of toxic substances in the nervous system, causing demyelination, inflammation, and progressive neurological deterioration. This deficiency is usually due to mutations in the GALC gene, leading to an autosomal recessive pattern of inheritance.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not a known enzyme related to Krabbe's disease. While sphingomyelinase is another lysosomal enzyme, it is associated with Niemann-Pick disease, a different type of sphingolipid storage disorder.
**Option B:** This option is incorrect because Krabbe's disease is not caused by a deficiency of galactosylceramidase, although it is a related enzyme. The correct enzyme is galactocerebrosidase (GALC).
**Option D:** This option is not relevant to Krabbe's disease, as the disorder is not associated with a deficiency of this enzyme or any other enzyme related to the breakdown of myelin.
**Clinical Pearl / High-Yield Fact**
Krabbe's disease is characterized by a range of symptoms, including developmental delay, seizures, muscle weakness, and vision loss, which typically appear in infancy or early childhood. The disease is often fatal, with most patients dying by the age of 5-10 years.
**Correct Answer:** C. Galactocerebrosidase (GALC)