Diseases

Homogentisic Acid Oxidase Deficiency

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A deficiency of the hepatic enzyme homogentisate 1,2-dioxygenase (HGO) forces the accumulation of homogentisic acid, which is rapidly cleared in the kidney and excreted. Upon contact with air, homogentisic acid is oxidized to form a pigmentlike polymeric material responsible for the black color of standing urine.

SYMPTOMS

Dark spots in the sclera (white) of your eyes.
Thickened and darkened cartilage in your ears.
Blue speckled discoloration of your skin, particularly around sweat glands.
Dark-colored sweat or sweat stains.
Black earwax.
Kidney stones and prostate stones.

CAUSES

It is caused by a mutation on your homogentisate 1,2-dioxygenase (hgd) gene. It's an autosomally recessive condition. This means that both of your parents must have the gene in order to pass the condition on to you. Alkaptonuria is a rare disease.