Homocysteine

An amino acid that is produced by the human body, usually as a byproduct of consuming meat. Homocysteine is normally converted into other amino acids. An abnormal accumulation of homocysteine, which can be measured in the blood, can be a marker for the development of heart disease.

• Homocysteine is an amino acid. Amino acids are the building blocks of proteins.
• Homocysteine levels increase in the body when the metabolism to cysteine of methionine to cysteine is impaired.
• Having elevated levels of homocysteine in the blood (hyperhomocysteinemia) is associated with atherosclerosis and blood clots.
• You can’t get homocysteine from your diet.
• Foods containing methionine are transformed into homocysteine in the bloodstream.
• Cysteine is an important protein in the body that has many roles.
• If homocysteine cannot be converted into cysteine or returned to the methionine form

Homocysteine is an amino acid produced when proteins are broken down. A high homocysteine level, also called hyperhomocysteinemia, can contribute to arterial damage and blood clots in your blood vessels.

High homocysteine levels usually indicate a deficiency in vitamin B-12 or folate.

Higher levels of homocysteine are split into three main categories:

• Moderate: 15-30 mcmol/L
• Intermediate: 30-100 mcmol/L
• Severe: greater than 100 mcmol/L

Many factors contribute to high homocysteine levels. If you have a folate or B vitamin deficiency, you may develop hyperhomocysteinemia.

Other risk factors include:

• low thyroid hormone levels
• psoriasis
• kidney disease
• certain medications
• genetics

Your doctor can perform a simple blood test to measure how much is in your bloodstream. This can also detect if you’ve developed a vitamin deficiency or identify the cause of unexplained blood clots.

Your doctor may require you to fast a few hours before the test. Certain medications or vitamin supplements can affect your results. Talk to your doctor about any medications you’ve been taking prior to this test.

Results are usually available within 24 hours.

Hyperhomocysteinemia itself usually does not cause any symptoms in adults, though it can in children. Symptoms can also vary from one person to the next and be subtle.

Doctors may order a homocysteine test if they suspect you have a vitamin deficiency, and if you begin exhibiting symptoms of a vitamin deficiency.

Symptoms of a vitamin B-12 deficiency include:

• pale skin
• weakness
• fatigue
• tingling sensations (like pins and needles) in the hands, arms, legs, or feet
• dizziness
• mouth sores
• mood changes

If you test positive for elevated homocysteine levels, you could be at an increased risk of developing a number of health issues. Some common conditions associated with high homocysteine are:

• osteoporosis, or bone thinning
• atherosclerosis, or a buildup of fats and other substances in the arterial walls
• thrombosis, a blood vessel blood clot
• venous thrombosis, a blood clot in the veins
• heart attack
• coronary artery disease
• stroke
• dementia
• Alzheimer’s disease