Total Shoulder Reverse Arthroplasty in Alkaptonuria: An Effective Option to Treat a Complication of a Rare Disease.

Introduction: Alkaptonuria (AKU) is a rare autosomal recessive disorder in which tyrosine metabolism is altered. There is a deficiency of the Homogentisate 1,2-dioxygenase enzyme (homogentisic acid oxidase) This enzyme is responsible for the metabolism of the tyrosine - homogentisic acid - in maleylacetoacetic acid. Accumulation of homogenous acid occurs in urine and conjunctival tissue in the second with important deleterious effects on cartilage and bone.