Lab Minute: MTHFR

Dr. Stacey Clardy discusses methylenetetrahydrofolate reductase (MTHFR) in this lab minute.   Show transcript:  Dr. Stacey Clardy: Hi, this is Stacey Clardy from the Salt Lake City VA in the University of Utah. Let's do a lab minute today on MTHFR. This one just simply will not go away. This is one of those topics where a huge amount of patient anxiety is inversely proportional to the utility of a test. So MTHFR is methylenetetrahydrofolate reductase. It's the enzyme that helps generate five methyltetrahydrofolates supporting remethylation of homocysteine to methionine. That biochemistry does matter because the clinical leap that often follows is the problem. So the common polymorphisms of MTHFR are C677T and A1298C. They are widespread in the general population. A recurring misunderstanding is that ordering MTHFR genotyping in a thrombophilia evaluation or as a catchall explanation for you name it, migraines, neuropathy, psychiatric symptoms, nondescript inflammation, is going to give you the answer. The best evidence-based guidance is that MTHFR polymorphism testing has minimal clinical utility and should not be ordered routinely, particularly not as part of a thrombophilia evaluation.So what do we do when a patient arrives with one of these MTHFR results and they are concerned? I try to translate into what actually matters clinically. If there is a concern for thrombotic risk or a documented thrombotic risk event, I focus on established thrombophilias and clinical risk factors and not common MTHFR isolated variants. Now, if the concern is folate metabolism and homocystine, well, we can actually measure those nutritional markers and homocystine. And so if homocystine is elevated, the next thing I'll do is consider the context. And if their folate is low or if one of their B vitamins is low, I replace it rather than building a medical mythology around a genotype that's not going to change the management for most patients. So that's an approach and an update to MTHFR. I hope it's helpful. This is Stacey Clardy, until next time.