Abstract

Alkaptonuria is a rare autosomal recessive multisystem disorder of phenylalanine/tyrosine metabolism which occurs due to lack of homogentisic acid oxidase, which causes homogentisic acid deposition in the tissues. Alkaptonuria is characterized by a triad of homogentisic aciduria, oochronosis, and precious degenerative arthropathy. Oochronosis is blue-blackish discoloration of skin and cartilage involving multiple sites like ear pinna, cheeks, palms, soles, etc as well as urine that turns black upon standing.