Question

HIAA in urine present in?

• A. Alkaptonuria
• B. Albinism
• C. Carcinoid
• D. Phenylketonuria

Answer 1

The Correct Option is C

5-Hydroxyindoleacetic acid (HIAA) is mainly a breakdown product of serotonin, a neurotransmitter sourced primarily from tryptophan. Elevated HIAA levels in urine are indicative of specific medical conditions. To determine which condition corresponds with raised HIAA levels, let's analyze the given options:

• Alkaptonuria: Characterized by a deficiency in homogentisate oxidase, leading to accumulation of homogentisic acid, resulting in dark urine upon standing. HIAA is not implicative of this disorder.
• Albinism: A group of genetic conditions marked by a deficit in melanin production. This condition does not involve serotonin degradation, thus unrelated to HIAA.
• Carcinoid: This syndrome is associated with neuroendocrine tumors, typically from the small intestine, which produce harmful amounts of serotonin. The breakdown of excess serotonin significantly elevates HIAA levels in the urine.
• Phenylketonuria (PKU): An inherited disorder where phenylalanine builds up due to lack of phenylalanine hydroxylase. Similar to alkaptonuria, it does not involve HIAA production.

Given these analyses, Carcinoid tumors result in increased serotonin, and thus high HIAA levels in urine. Therefore, of the indicated options, Carcinoid is correctly correlated with HIAA presence in urine.