MCQ – 136679

Which of the following is deficient in the mucopolysaccharidosis associated with Natowicz disease?

Correct Answer � D Explanation

Hyaluronic Acid

• Natowicz disease is a very rare form of mucopolysaccharidosis (MPS), more specifically a hyaluronidase deficiency.

• This leads to the accumulation of hyaluronic acid, a glycosaminoglycan (GAG) that is normally degraded by hyaluronidase.

• Hence, hyaluronic acid is not broken down properly, resulting in its deficiency of degradation and accumulation, which underlies the pathology.

• This distinguishes Natowicz disease from other types of MPS, where the usual accumulating GAGs are heparan sulfate, dermatan sulfate, or keratan sulfate.

Why Other Options Are Incorrect:

A. Dermatan Sulfate

• Accumulates in Hurler syndrome (MPS I) and Hunter syndrome (MPS II) due to iduronidase or iduronate sulfatase deficiency.

• Not involved in Natowicz disease.

B. Heparan Sulfate

• Accumulates in Sanfilippo syndrome (MPS III) and some other MPS types.

• Natowicz disease does not involve its metabolism.

C. Keratan Sulfate

• Involved in Morquio syndrome (MPS IV) due to deficiency of enzymes like galactosamine-6-sulfatase.

• Not associated with Natowicz disease.