Which genetic disorder is characterized by a deficiency in homogentisate oxidase?

A deficiency in homogentisate oxidase leads to the accumulation of homogentisic acid, resulting in the metabolic disorder known as alkaptonuria. This condition is characterized by the excretion of excess homogentisic acid in the urine, which can cause the urine to turn dark when exposed to air. Additionally, patients with alkaptonuria may develop symptoms such as ochronosis, where connective tissues (such as cartilage) become darkened and damaged due to the deposition of homogentisic acid.

Alkaptonuria is an autosomal recessive disorder and is often considered a variant of tyrosine metabolism disorders. The accumulation of intermediates due to enzyme deficiencies in metabolic pathways like this is a key concept in understanding genetic metabolic disorders. In contrast, the other listed conditions involve different enzymes and metabolic alterations, reinforcing the unique nature of alkaptonuria linked directly to homogentisate oxidase deficiency.