Minocycline-induced Cartilage Hyperpigmentation Mimicking Alkaptonuria in a Patient with Knee Pain.

Abstract

Ochronosis is the bluish-black discoloration of tissues typically due to the rare autosomal-recessive metabolic disorder alkaptonuria, caused by a mutation of the HGD gene on chromosome 3. This gene mutation results in a deficiency of homogentisate 1,2-dioxygenase, leading to the accumulation and deposition of homogentisic acid in cartilage and other connective tissues. …