Alkaptonuria (AKU), also referred to as black bone disease, is a very rare condition resulting from the lack of an enzyme in the metabolic pathway of the amino acid, tyrosine. The lack of enzyme leads to a build-up in the body of the metabolite, homogentisic acid. This acid can turn urine and parts of the body a dark colour and, over time may lead to a range of issues.
AKU is an inborn error of metabolism. Therefore, it is present from birth. However, early signs of the condition may be missed or overlooked, and so AKU may go unnoticed until adulthood, when symptoms are more obvious.
Certain patients with AKU may be treated with a medication; a side effect of which is an increase in blood tyrosine levels. An individual with AKU, and excessively high tyrosine levels, is referred to as having a condition called tyrosinaemia.
Protein substitutes which are free from, or low in tyrosine (and phenylalanine), may support an adequate protein intake in patients who are following a protein restriction. They may also help to keep blood tyrosine levels within normal limits.
For further information please contact your local Vitaflo representative.
Inborn Errors of Metabolism
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