Alkaptonuria

Rather rare (one in 200,000 births) inherited disorder of protein metabolism characterized by an inability of the body to metabolize the amino acids tyrosine and phenylalanine. In the normal metabolic pathway of tyrosine, homogentisic acid is converted to maleylacetoacetate in the liver by the enzyme homogentisate 1,2-dioxygenase. This enzyme is not active in individuals