The symptoms depend on the variant you carry and can vary from person to person. The presence of the MTHFR mutation cannot just be confirmed by the symptoms. Only a genetic test is qualified to confirm the mutation. Some conditions that have been shown to have an association with the MTHFR mutation include:
Depression
Anxiety
Heart diseases
Blood clotting problems
Migraine
Seizures
Bipolar disorder
Developmental delay
Microcephaly
Colon cancer
Chronic pain and fatigue