homocysteine By Ivan Suarez Robles 07 Feb, 2011 A sulfur containing amino acid. Considered a risk factor for cardiovascular disease and possibly neurodegeneration.Related Articles: Glossary: folic acidGlossary: methionine cycleGlossary: methionine synthase (MS)Glossary: methyltetrahydrofolate (methylTHF)Glossary: total homocysteine (tHcy)