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A woman who has ZERO Vitamin D in her blood, even with supplementation – March 2019

Vitamin D–Binding Protein Deficiency and Homozygous Deletion of the GC Gene

March 21, 2019
N Engl J Med 2019; 380:1150-1157 DOI: 10.1056/NEJMoa1807841
Clark M. Henderson, Ph.D., Susan L. Fink, M.D., Ph.D., Hanan Bassyouni, M.D., Bob Argiropoulos, Ph.D., Lindsay Brown, Ph.D., Thomas J. Laha, M.T. (A.S.C.P.), Konner J. Jackson, B.S., Raymond Lewkonia, M.B., Ch.B., Patrick Ferreira, M.B., B.S., Andrew N. Hoofnagle, M.D., Ph.D., and Julien L. Marcadier, M.D.

VitaminDWiki

The measured Vitamin D in the blood is semi-activated Vitamin D
 
It is carried by Vitamin D binding protein
 
A large % of the activated vitamin D which gets to the tissues of the body was never semiactivated vitamin D in the blood
 
"Large %" estimates range from 50% to 90
 
This woman does have fully activated vitamin D in her tissues, but it was probably fully locally, and not by the liver & kidneys
 
Her body just uses the right pathway of the diagram below

Blood Test Misses a lot (VDW 3439)
This study appears to be unaware of the right-hand pathway


See also VitaminDWiki

The following are cases where there is a poor Vitamin D binding protein
The woman has an extreme case, ZERO VDBP


A 58-year-old woman with debilitating ankylosing spondylitis who was born to consanguineous parents was found to have an apparent severe vitamin D deficiency that did not respond to supplementation. Liquid chromatography–tandem mass spectrometry showed the absence of circulating vitamin D–binding protein, and chromosomal microarray confirmed a homozygous deletion of the group-specific component (GC) gene that encodes the protein. Congenital absence of vitamin D–binding protein resulted in normocalcemia and a relatively mild disruption of bone metabolism, in this case complicated by severe autoimmune disease.
(Funded by the National Institutes of Health and the University of Washington.)

Part of the description at Medical Express
First case of person without the protein needed to transport vitamin D identified

  • "The idea has always been that without its binding protein, vitamin D couldn't get to the cells where it's needed. Our findings call that into question," says Dr. Julien Marcadier, MD, a clinical assistant professor in the departments of medical genetics and paediatrics at the Cumming School of Medicine and senior author of the paper. "To our surprise, she's maintained normal calcium levels despite having no measurable vitamin D. This tells us that the vitamin D she has in her system does in fact get to its target cells, though how exactly that happens is still unknown."
  • This is the first reported case of a human without vitamin D binding protein. The woman, who does not wish to be identified, is now taking vitamin D at a dose of 2,000 IU per day and has not suffered any recent fractures. She continues to work with her health-care team as they try to better understand the role of vitamin D binding protein.


Created by admin. Last Modification: Thursday May 16, 2019 21:33:18 GMT-0000 by admin. (Version 5)
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