Hyperhomocysteinemia

Hyperhomocysteinemia is a medical condition characterized by an abnormally high level of total homocysteine (that is, including homocystine and homocysteine-cysteine disulfide) in the blood, conventionally described as above 15 μmol/L.

As a consequence of the biochemical reactions in which homocysteine is involved, deficiencies of vitamin B₆, folic acid (vitamin B₉), and vitamin B₁₂ can lead to high homocysteine levels. Other possible causes of hyperhomocysteinemia include genetics, excessive methionine intake, and other diseases.

Hyperhomocysteinemia is typically managed with vitamin B₆, vitamin B₉ and vitamin B₁₂ supplementation. Hyperhomocysteinemia is a risk factor for cardiovascular disease; supplements of these vitamins may slightly reduce stroke outcome but not myocardial infarction, death from any cause or adverse events.