Accumulation of large amounts of homogentisic acid in the urine is the result of which of the following disorders?
A) Alkaptonuria
B) Tyrosyluria
C) PKU
D) Homocystinuria

Question

Quizplus · Accepted Answer

Accumulation of large amounts of homogentisic acid in the urine is characteristic of alkaptonuria, an autosomal recessive disorder caused by a deficiency in the enzyme homogentisic acid oxidase, which leads to the accumulation of homogentisic acid in the tissues and its eventual excretion in the urine as a dark pigment called “ochronosis”. Tyrosyluria is a rare inborn error of metabolism which is caused by a defect in tyrosine metabolism. PKU (phenylketonuria) is caused by a deficiency in the enzyme phenylalanine hydroxylase. Homocystinuria is caused by a deficiency in one of several enzymes involved in homocysteine metabolism.

Accumulation of Large Amounts of Homogentisic Acid in the Urine