Homocysteine

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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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• What is homocysteine?
• Why is it important to monitor homocysteine levels?
• What are the possible symptoms and signs of elevated homocysteine levels?
• What is considered high homocysteine levels?
• What causes elevated homocysteine levels?
• Can elevated homocysteine levels be hereditary?
• How can homocysteine levels be lowered?
• Can lowering homocysteine levels prevent the risk of heart disease, heart attacks, and strokes?
• Who should have their homocysteine levels tested?
• Synonyms and Keywords
• Author and Editor

Homocysteine is one of the 20 amino acids (molecules that the body requires to synthesize all body proteins). It is not possible to get homocysteine from the diet, so it must be made from other amino acids that can be consumed in the diet, such as methionine (found in meat, fish, and dairy products). Vitamin B6 (pyridoxine), vitamin B12 and folic acid are needed to help these reactions occur.

Foods containing methionine are transformed into homocysteine in the bloodstream. Homocysteine is converted in the body to cysteine, with vitamin B6 facilitating this reaction. Homocysteine can also be recycled back into methionine using vitamin B12-related enzymes.

Cysteine is an important protein in the body that has many roles. It is involved in the way proteins within cells are folded, maintain their shape, and link to each other. Cysteine is a source of sulfide and is part of the metabolism of different metals in the body including iron, zinc and copper. Cysteine also acts as an anti-oxidant.

If homocysteine cannot be converted into cysteine or returned to the methionine form, levels of homocysteine in the body increase. Elevated homocysteine levels have been associated with heart attack, stroke, blood clot formation, and perhaps the development of Alzheimer's disease.

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