Diseases

Alkaptonuria

Back

Alkaptonuria. ... Deficiency of this enzyme leads to the three cardinal features of alkaptonuria (the presence of homogentisic acid in the urine), ochronosis (bluish-black pigmentation in connective tissue), and arthritis. Urine that turns dark is a characteristic feature.

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

Alkaptonuria 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.