My friend had a miscaraige and the doctors told her she had a blood problem.
Has your friend also been tested for Antiphospholipid Antibody Syndrome?
However, MTHFR in itself can cause miscarriage. I highly suggest that you friend be followed by a hematologist and when she is ready to become pregnant again by a perinatologist.
MTHFR – methylene tetra hydro folate reductase
MTHFR is a gene that is responsible for making an enzyme called methylenetetrahydrofolate reductase. This enzyme plays a role in processing amino acids (the building blocks of proteins) and for a chemical reaction involving forms of the vitamin folate, which is also called folic acid or vitamin B9. Specifically, this enzyme converts 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate. This reaction is required for the multistep process that converts the amino acid homocysteine to another amino acid, methionine.
When MTHFR gene is defective ( 1defect or 2 defective genes) the levels of homocysteine in the body goes up (homocystinuria). It may also play a role in the risk of high blood pressure in pregnancy (preeclampsia) and may be a risk factor for birth defects that occur during the development of the brain and spinal cord (neural tube defects). High homocysteine levels is “toxic” causing damage to the developing placenta tissues resulting in spontaneous miscarriages and somehow caustic to the endothelium tissue lining blood vessels. (that is why your friend had miscarriage).