You Need Vitamin D to Live. How Could This Woman Survive With None in Her Blood?

You Need Vitamin D to Live. How Could This Woman Survive With None in Her Blood?

In 1992, a 33-year-old Lebanese woman had just immigrated to Canada and went to see a doctor. She was hunched over, and had limited mobility in her lower back, neck, shoulders and hips. Her doctor, Raymond Lewkonia at the University of Calgary, diagnosed her with ankylosing spondylitis, a medical condition that causes vertebrae in her spine to fuse, and thought that was it.

Then, about eight years later, the woman had a series of fractures in her ribs, feet, left arm and right hip. Her doctor had her take vitamin D supplements, but they had no effect: Lab tests revealed that she didn’t have any vitamin D circulating around in her blood.

That seemed impossible. Some vitamin D, after all, is thought to be essential for maintaining bone health, and taking supplements after a bone injury or fracture is commonly used to expedite the healing process. Why was none of this vital substance in the woman’s system?

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A medical geneticist who looked at this case, Dr. Patrick Ferreira, suspected that a binding protein that partners with vitamin D to get in and around the body — or a lack of it — might have something to do with this medical mystery. But losing the ability to transport vitamin D would be lethal to humans, according to what doctors conventionally know.

Dr. Ferreira set out to test his hypothesis, but had trouble confirming that the vitamin D binding protein was indeed missing in the woman’s system. He and others sent blood samples to labs in Europe and Vancouver, but these tests — which can be unreliable — came back saying that binding protein levels were normal. When Dr. Ferreira retired, he passed the patient’s case to his colleague, Dr. Julien Marcadier, a clinical geneticist at Alberta Children’s Hospital Research Institute, now the lead author of a case report published last month in The New England Journal of Medicine.

Fortunately for Dr. Marcadier, researchers at the University of Washington in Seattle had just developed a more sensitive method of detecting the protein.

Dr. Andrew Hoofnagle and his colleagues agreed to examine the blood sample, and found that there was no vitamin D in her blood, or any vitamin D binding protein.

“When you think about the biology of vitamin D,” Dr. Hoofnagle said, “that shouldn’t work. That person should not be alive.”

Martin Hewison, a molecular endocrinologist at the University of Birmingham in England, who was not involved in the study, says that this case is the first of its kind.

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