Researchers have finally solved an 80-year-old mystery related to the baby boom of the 1930s and ’40s.
This deadly ingredient is found in household staples—milk, bread, cereal, margarine.
But it was put in there to make the kids healthier. In the early 1900s, more than 80 percent of children suffered from rickets, so vitamin D was added to foods.
Fortifications all but eradicated the disease. However, this measure has fatal side effects, as some infants cannot metabolize vitamin D properly.
They suffer from diseases that cause calcium to build up in the blood, leading to kidney damage and kidney stones, which can be fatal for babies.
By the 1950s, outbreaks of vitamin D toxicity in infants led many European countries to ban vitamin D fortification.
Research in 2011 showed that the disorder, now known as infantile hypercalcemia type 1, or HCINF1, is caused by a genetic mutation.
But scientists struggled to find that the roughly 10 percent of patients affected by HCINF1 did not have the genetic mutation.
As a result, many infant deaths and symptoms that patients still experience today remain unexplained.
Read more from Sky News:
Children at increasing risk of deadly disease
How many spare beds does your hospital have?
Why laughing gas faces a ban
Mystery ‘very scary’ for affected mother
But now, researchers at the University of East Anglia (UEA) have discovered what these patients suffer from – not because of a genetic mutation, but because of their shape.
Lead researcher Dr Darrell Green, from UEA’s Norwich Medical School, said most patients who were screened and found to have HCINF1 also had a mutation in the CYP24A1 gene.
If people don’t have the mutation but still have trouble processing vitamin D, they may go on to “have problems for life without a proper diagnosis,” he said.
Problems faced by patients may include recurrent kidney stones and severe pain.
Shelley O’Connor, 34, from Norwich, was only diagnosed with HCINF1 11 years ago when she was 23 and pregnant with her first child.
When she started taking pregnancy supplements, including vitamin D, to help her baby, she started experiencing severe pain, leading midwives to think she was due at 23 weeks.
“It’s pretty scary,” she said. “I was really worried about the baby but when I did the MRI they found it was actually a kidney stone from taking vitamin D as a pregnancy supplement.”
‘Abnormal’ gene shape solves puzzle
The UEA team teamed up with colleagues at Norfolk and Norwich University Hospitals, where they worked with 47 patients like Shelley to understand how people develop the disease without the mutation.
They used a combination of next-generation genetic sequencing and computational modeling to study blood samples from this 10 percent of “suspect patients.”
“Nicole Ball, a doctoral student in my lab, performed more extensive genetic analysis of blood samples from six patients, and we found that the physical shape of the CYP24A1 gene in these HCINF1 patients was abnormal,” said Dr. Green.
“This tells us that gene shape is important in gene regulation — which is why some people have HCINF1 but are not definitively diagnosed,” he added.
Dr. Green explains the difference between genetic mutations and genetic shape in DNA sequencing, and what this means for patients.
“On a broader scale related to genetics and health, we know that genes have to have the right sequence to make the right protein, but at a more complex level, we now know that genes also have to have the right physical shape”
The researchers now plan to study the role of genetic shape in other diseases, including cancer.