The numerous reports on alkaptonuria are limited to degenerative manifestations in joints, but there are very few reports of the effects of the deposition of homogentisic acid
in tendons leading to spontaneous rupture.
Alkaptonuria (AKU) is a rare metabolic, autosomal recessive disorder in the phenylalanine and tyrosine catabolic pathway that is characterized by the accumulation of homogentisic acid
(HGA; homogentisic aciduria) in the body, especially in the connective tissues (cartilage, tendons, and ligaments) (1) Alkaptonuria is caused by mutations in the homogetisate 1.2-dioxygenase gene (HGD), which lead to a lack of HGD enzyme activity.
Fifteen standard phenolic compounds, including gallic acid, pyrogallol, homogentisic acid
, protocatechuic acid, (+) catechin, chlorogenic acid, caffeic acid, vanillin, ferulic acid, naringin, resveratrol, naringenin, hesperetin, formononetin, biochanin-A were purchased from Sigma Aldrich and used for calibration curves.
Sbou' explained that Alkaptonuria is caused by deficiency of the enzyme homogentisic acid
oxidase (HGO), as a consequence of the enzymatic block, the homogentisic acid
(HGA) accumulates in body tissues, vertebrae, joints and heart valves,.
For example, a dark yellow to orange color may signify the presence of bilirubin, which is indicative of liver disease and/or biliary-tract obstruction, while brown and/or black urine may be caused by the presence of melanin or homogentisic acid
. Importantly, neither melanin nor homogentisic acid
are detected in a routine urinalysis, therefore careful attention to the color of urine can provide an important clue to an underlying disease process.
Ochronosis results from a deficiency of homogentisic acid
oxidase and leads to deposition of homogentisic acid