Alkaptonuria (HGD)

Alkaptonuria is an autosomal recessive disorder caused by pathogenic variants in the gene HGD. This disorder is characterized by accumulation of homogentisic acid leading to urine turning black when exposed to air, pigmentation of connective tissues such as cartilage and skin (ochronosis), joint and spine arthritis, and destruction of the cardiac valves. Individuals may also develop kidney stones or prostate stones. No clear genotype-phenotype correlation has been established.

For information about carrier frequency and residual risk, please see the residual risk table.

This gene is included on the following panel(s):