The world's first woman without vitamin D in her body
A Lebanese woman who immigrated to Canada is the first known case of having no vitamin D or any vitamin D-binding protein in her blood.
In 1992, a 33-year-old woman who had recently immigrated to Canada went to see a doctor with a hunchback and difficulty moving her lower back, neck, and hips. Dr. Raymond Lewkonia of the University of Calgary diagnosed her with ankylosing spondylitis, which causes the vertebrae of the spine to fuse together.
Eight years later, the woman suffered a series of fractures in her ribs, foot, left arm, and right hip. Doctors prescribed vitamin D, but it was ineffective. Tests showed no vitamin D circulating in her blood.
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Photo of woman's broken ribs. Photo:BSIP/UIG. |
This is unlikely. Vitamin D is thought to be essential for maintaining bone health and is often supplemented to help bones heal faster after a fracture or injury.
Geneticist Patrick Ferreira suspects that the patient lacks a protein that binds to vitamin D to get it into circulation in the body, which is linked to this mysterious condition. However, without the ability to transport vitamin D, people cannot survive.
Dr. Ferreira tested his hypothesis by sending blood samples from patients to labs in Europe and Vancouver, but still couldn't find a cause. After he retired, Dr. Julien Marcadier, a clinical geneticist at the Alberta Children's Hospital Research Institute, took over the research.
AboveThe New England Journal of MedicineIn March 2019, Dr. Marcadier said researchers at the University of Washington helped test the woman’s blood. The results showed that this was the first case in the world where there was no vitamin D or any vitamin D-binding protein in the blood.
So how did the woman survive nearly six decades without vitamin D in her body? According to Dr. JoAnn Manson, an endocrinologist and investigator at Brigham and Women’s Hospital in Boston, different organs require different amounts of vitamin D. The free vitamin D that the woman got from food and sunlight may have been enough to grow bones and sustain life.
In addition, science has not yet determined exactly how much vitamin D the human body needs. Some studies indicate that vitamin D levels may not be related to bone density or fractures in the elderly.
"I don't think this patient's case suggests that the body needs less vitamin D, just that the human body can adapt well to limited amounts of vitamin D binding protein," said Dr. Ellen Fung, director of the Bond Density Clinic at the Children's Hospital Oakland Research Institute in California.