Alkaptonuria (AKU, OMIM: 203500) is a rare autosomal recessive disorder of tyrosine metabolism resulting from a defect in homogentisate‐1,2‐dioxygenase (HGD, E.C.1.12.11.5), which leads to a marked increase in the circulating concentration of homogentisic acid (HGA).1 The pathological hallmark of AKU is “ochronosis,” which is a consequence of the deposition of a dark pigment in connective tissue, mainly cartilage, which alters its physicomechanical properties. This evidence concerns the gene HGD and alkaptonuria.