With the advent of genetic testing (see the MTHFR page on STTM), some people have discovered they have a Vitamin D25 Receptor Mutation, known as VDR BSM.

The VDR gene encodes your vitamin D receptor. If you have a mutation of this gene, it can influence the density of your bone minerals in a negative way, causing increased risk of osteoporosis or bone fractures. It might even contribute to hyperparathyroidism or Rickets Type II.

Folks with this mutation convert vitamin D to vitamin D1,25, the active form of Vitamin D, but their Total Vitamin D 25 (the 25-hydroxy vitamin D) may be low because it’s converting to the Vitamin D1,25. Unfortunately, doctors aren’t checking the Vitamin D1,25 levels, which has a short half life, and they and you need to.

If you have too much of the active Vitamin D1,25, there is a possibility that the thyroid hormone T3 may not get to your cells well from being blocked thanks to the high D1,25. Says the website gettingstrong.org:  “The excess 1,25-D can cause problems with other secosteroid receptors in the body, such as the thyroid receptor”. But we need more information to confirm this…so don’t take it as gospel yet!!

Bottom line: it can be wise to check both D3 and D1,25.