Ochronosis

Ochronosis, often called alkaptonuric ochronosis,^[1] is an autosomal recessive metabolic disorder that causes an excess of homogentisic acid, resulting in adverse pigmentation, calcification, and inflammation of cartilagenous and related tissue throughout the body.

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The disorder is a result of incomplete metbolism of homogentisic acid, tyrosine and phenylalanine.

The face, skeletal system, cardiovascular system,^[2] respiratory system, urinary system and to a lesser degree, the skin, are affected by this disease.

Symptoms

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.^[1] 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.

See also

• Alkaptonuria
• Tyrosinemia
• Phenylketonuria

References