<unk>  is a dermatological disorder that results in the adverse pigmentation of cartilage from a long term buildup of phenylalanine or tyrosine.
In this disorder, a pigment substance resulting from incomplete catabolism of tyrosine and phenylalanine is deposited, over the years, in cartilage, the eye, and to a lesser degree in the skin.
Ochronosis
Lead poisoning
Skeletal fluorosis
Gold poisoning
Hypervitaminosis D
Mercury poisoning
Hypervitaminosis A
Albinism