Serum Total Homocysteine Level: A True Cardiovascular Risk Factor or an Acute Phase Reactant Protein?

Atherosclerosis is the leading cause of death in the developed world1.In Pakistan; the disease seems to follow an accelerated course with ischaemic events occurring a decade earlier than those reported worldwide2. While many risk factors of cardiovascular diseases are well established, many are still under evaluation; like homocysteine, which is now being considered an independent risk factor for cardiovascular diseases3.Homocysteine is a sulfur containing amino acid which is not our dietary constituent but is formed by metabolism of methionine, another amino acid present in our daily protein diet. In case of excess formation of homocysteine as compared to its consumption, it appears in urine if levels are too high3. Normal plasma homocysteine concentration ranges from 5 to 15μmol/litre. Of this, almost 75% is bound to proteins, especially albumin, through disulfide bond. Classification of hyperhomocysteinemia described by Kang SS 4 is followed widely.Moderate hyperhomocysteinemia (15 to 30 μmol/litre)Intermediate hyperhomocysteinemia (30 to 100μmol/litre)Severe hyperhomocysteinemia (>100 μmol/litre