Homocysteinuria

It is a genetic disorder that runs in certain families which can lead to the lack of an enzyme, cystathionine-B synthetase. The result is excess accumulation of homocystine in the blood and urine. An abnormally high level of homocystine leads to damage of the blood vessels, promotes arteriosclerotic plaques and can also damage connective tissue, which is the framework of bones and joints. Fortunately, homocysteinuria in its severe form is very rare. Most people who suffer from mild homocysteinuria have it because they are deficient in one of three vitamins: folic acid, B6 and B12, which are needed to metabolize homocystine. In these cases a mild to moderate megaloblastic anaemia can be present.

Synonym: Methylcobalamine congenital deficiency