Mondo Description A disorder characterized by bluish-black discoloration of the cartilaginous tissues due to accumulation of homogentisic acid. It is associated with alkaptonuria. Signs and symptoms include dark urine, skin pigmentation, and arthritis.

Disease Ontology Description A connective tissue disease characterized by bluish-brown discoloration of connective tissues that develops from the deposition of homogentisic acid and subsequent oxidation and polymerization reactions.