ALKAPTONURIC OCHRONOSIS AND ARTHROPATHY: A RARE CASE

Alkaptonuria is a rare autosomal recessive metabolic disorder resulting in a deficiency of homogentisic acid oxidase. Thus homogentisic acid accumulates in cells and body fluids and its oxidized polymers bind to collagen, leading to progressive deposition of grey to bluish black pigment resulting in degenerative changes in cartilage, intervertebral disc and other connective tissues, leading to arthritis which is the only disabling effect in an affected older individual. Alkaptonuria is a progressive disease and the three main features, according the chronology of appearance are: darkening of the urine at birth, then ochronosis(blue-black pigmentation of the connective tissue) clinically visible at around 30 years in the ear and eye, and finally a severe ochronotic arthropathy at around 50 years with spine and large joint involvements.