If the diagnosis of alkaptonuria is suspected, this can be confirmed or excluded by collecting urine for twenty-four hours and determining the amount of homogentisic acid by means of chromatography.
12.
Apart from treatment of the complications ( such as joint replacement for the cartilage damage ), vitamin C has been used to reduce the ochronosis and lowering of the homogentisic acid levels may be attempted with a low-protein diet.
13.
False positive reaction can be due to the presence of other reducing substances in urine such as ascorbic acid ( during intake of vitamin supplements ), drugs ( levodopa, contrast used in radiological procedures ) and homogentisic acid ( alkaptonuria ).
14.
Nitisinone inhibits the enzyme, 4-hydroxyphenylpyruvate dioxygenase, responsible for converting tyrosine to homogentisic acid, thereby blocking the production and accumulation of HGA . Nitisinone has been used for some time at much higher doses in the treatment of type I tyrosinemia.
