Posted by Larry Hoover on February 14, 2005, at 7:42:02 [reposted on February 14, 2005, at 18:37:38 | original URL]
In reply to possible errors in folate metabolism, please help, posted by Becca10 on February 12, 2005, at 21:25:32
> Hi,
> I was wondering if there are any biochemistry whizzes out there. Several members of my family and I have elevated MCV, otherwise known as macrocytic anemia. In addition, we have below reference range levels of homocysteine and methylmalonic acid. Macrocytic anemia is normally associated with vitamin b12 or folate deficiency, but these in turn are associated with *elevated* levels of both homocysteine and methylmalonic acid, not decreased. Any ideas?
>
> Thank you in advance.
>
> BeccaAs you might imagine, the findings you have described (anemia, levels of homocysteine and methylmalonate) are part of a very complex metabolic system. These findings suggest a number of possibilities, but the only way to rule any our or in, is to do further testing. The familial nature of this cluster of findings may be due to genetic factors, but you can't simply exclude social factors; families tend to eat similar diets, even when living in different households.
With respect to further tests, I'm surprised you haven't mentioned your actual serum B12 levels. It's axiomatic in medicine to not start with folate supplementation until it is determined whether or not B12 is also abnormal.
As to a familial link with B12, what you may all share is an abnormal production of intrinsic factor. Intrinsic factor binds to B12, and promotes uptake from the gut. If you have antibodies to IF, you will have low B12 and low methylmalonate. What I'm saying is, your questions are rather open-ended. The treatment required depends quite heavily on just what abnormality is present.
As to disturbances in folate metabolism, innate (genetic) folate malabsorption shows shortly after birth, and can easily be fatal, so it's unlikely you all have *that*. You may, however, have poor conversion of folic acid into its active forms. Again, specific testing would be required. There are special folate-derivative supplements (e.g. folinic acid, biopterins), but they're rather expensive, and you'd want to know that you are targetting a specific defect.
There is a link between homocysteine and methylmalonate, as they both involve the amino acid methionine (that is the commonality), but methylmalonate has other metabolic sources.
In short, there are many different avenues of data-collection I would pursue (if I were supervising your care) before I would make any recommendations. Simply increasing your collective intakes of folate and B12 may indeed help, but it is also likely to obscure the reasons that this is a familial finding.
Best,
Lar
poster:Larry Hoover
thread:457518
URL: http://www.dr-bob.org/babble/health/20050105/msgs/457846.html