Homocysteinemia due to MTHFR deficiency
- 5,10 alpha methylenetetrahydro-folate reductase deficiency
- 5,10-alpha-methylenetetrahydro-folate reductase deficiency
- Homocysteinemia due to methylenetetrahydro-folate reductase deficiency
- Homocysteinuria due to methylenetetrahydro-folate reductase deficiency
- Homocysteinuria due to MTHFR deficiency
High homocysteine levels in the blood may also increase the risk of preeclampsia, miscarriage, and blood clots. In general, mild to moderate homocysteinemia has been associated with an increase risk developing blood clots in the veins often in the lower leg or calf, which can travel to the lung (i.e., pulmonary embolism). 
The Human Phenotype Ontology provides the following list of signs and symptoms for Homocysteinemia due to MTHFR deficiency. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms.
The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature.
The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined.
Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
- Homocystinuria. Genetics Home Reference (GHR). 2008; http://www.ghr.nlm.nih.gov/condition=homocystinuria. Accessed 3/16/2011.
- MTHFR. Genetics Home Reference (GHR). Februrary 2011; http://ghr.nlm.nih.gov/gene/MTHFR. Accessed 7/14/2011.
- Homocysteine. American Academy of Family Physicians. 2006; http://familydoctor.org/online/famdocen/home/articles/249.html. Accessed 5/13/2009.