Homocysteine is a methylation pathway marker that, when not optimal, signals that compounds are not being efficiently methylated, which can lead to inflammation. Some people discuss it as a 'caustic' chemical that 'burns' the inside of arteries. I wouldn't say that is true as it is more of a marker that intimal endothelial cells and other body cells are unhealthy (undernourished) and prone to becoming inflamed / oxidized / infiltrated with excess platelets / WBC's / LDL / etc that are trying to heal the sick tissue.
This imbalance is not solely in the CV system, though that is a very important system as far as homocysteine based inflammation goes (think heart and brain attacks).
The methylation pathway relies heavily on adequate broad spectrum B vitamins and thyroid hormone balance as cofactors for the enzymes to work properly to keep the pathway flowing and avoid the homocysteine marker elevation. So either or both deficiencies are the usual causes for elevated homocysteine levels. MTHFR gene abnormality / mutation can also be a cause but typically if thyroid replacement / balancing and / or B vitamin deficiency replacement brings homocysteine down........then are our genes at fault or our diets and environmental impact on our body function to blame??
Severe, read completely dysfunctional, MTHFR enzymes from severe genetic anomalies are rare and signaled by unresponsive and usually severely elevated homocysteine levels (think 20-30) and usually accompanied by severe and early onset CV events such as heart attacks or strokes in 20-30 year old patients.
The optimal level is 5-6.
Homocysteine should be a standard and yearly checked biochemical marker. There is no drug treatment as none is necessary for most elevations.
Yours in health,