Ochronosis 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. Pigmented cartilage may appear blue due to scattering phenomenon, and to a lesser degree this may be true for skin with dermal deposition of this pigment. The skin of the axilla is very likely to be pigmented due to deposits of homogentisic acid in sudoriferous glands in these areas. The clinical features of this metabolic disorder are dark urine, pigmentation of the skin and arthritis. Particularly helpful is the almost constant presence of a patch of pigmentation (gray to brown in color) in the sclera, between the margin of the cornea and the outer or inner canthus. Because of the bluish color produced by the deep pigmentation, this condition may be confused with argyria. Anabolism is the aspect of metabolism that contributes to growth. ... Tyrosine (from the Greek tyros, meaning cheese, as it was first discovered in cheese), 4-hydroxyphenylalanine, or 2-amino-3(4-hydroxyphenyl)-propanoic acid, is one of the 20 amino acids that are used by cells to synthesize proteins. ... Jump to: navigation, search The alpha-amino acid Phenylalanine exists in two forms, the D- and L- forms, which are enantiomers (mirror-image molecules) of each other. ... Jump to: navigation, search Cartilage is a type of dense connective tissue. ... Jump to: navigation, search Arthritis (from Greek arthro-, joint + -itis, inflammation) is a group of conditions that affect the health of the bone joints in the body. ... The sclera is the white outer coating of the eye. ... Jump to: navigation, search The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber and provides most of an eyes optical power [1]. Together with the lens, the cornea refracts light and consequently helps the eye to focus. ... Canthus (pl. ... There is also a village named Argyria in Greece (pronunciation: ar-YEE-ree-a) , see Argyria, Greece. ...

References

• Jeghers - New England Journal of Medicine, Vol. 231: 122 & 181,1944
• The University of Massachussets Online Article on Skin Pigmentation Disorders [1]