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What does heterozygous indicate in a MTHFR mutation test result?

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Posted on Fri, 10 Nov 2017
Question: I recently had an artery dissection which lead to a series of strokes. they did a lab test called mthfr mutation test that said I was Heterozygous. what does this mean?
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Answered by Dr. Olsi Taka (3 hours later)
Brief Answer:
The consequences are minor.

Detailed Answer:
I read your question carefully and I understand your concern.

Mutations in the MTHFR gene which codes an enzyme called MTHFR are thought to be responsible for changes in folic acid metabolism and raised levels of the amino acid homocysteine. Raised levels of homocysteine are linked with a higher risk for stroke including also arterial dissection.

Each gene in DNA contains two copies, called alleles. If a mutation is present in both copies then we say to be homozygous for that mutation, if it is present only in one of the copies then we say heterozygous. There may be different types of mutation, so there may be also the case where both alleles have a mutation but a different one, in that case it is called compound heterozygous, so you should make sure the term compound is not used in your results as well.

If indeed you are simply heterozygous, meaning only one of the two copies carries a mutation, the other works fine. As a result the consequences are minor, depending on the mutation type the alterations in the folate metabolism are from none to mild. It is the homozygous and compound heterozygous which are linked to more significant changes.

I remain at your disposal for other
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar
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Dr. Olsi Taka

Neurologist

Practicing since :2004

Answered : 3654 Questions

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What does heterozygous indicate in a MTHFR mutation test result?

Brief Answer: The consequences are minor. Detailed Answer: I read your question carefully and I understand your concern. Mutations in the MTHFR gene which codes an enzyme called MTHFR are thought to be responsible for changes in folic acid metabolism and raised levels of the amino acid homocysteine. Raised levels of homocysteine are linked with a higher risk for stroke including also arterial dissection. Each gene in DNA contains two copies, called alleles. If a mutation is present in both copies then we say to be homozygous for that mutation, if it is present only in one of the copies then we say heterozygous. There may be different types of mutation, so there may be also the case where both alleles have a mutation but a different one, in that case it is called compound heterozygous, so you should make sure the term compound is not used in your results as well. If indeed you are simply heterozygous, meaning only one of the two copies carries a mutation, the other works fine. As a result the consequences are minor, depending on the mutation type the alterations in the folate metabolism are from none to mild. It is the homozygous and compound heterozygous which are linked to more significant changes. I remain at your disposal for other