Scientists have discovered a genetic defect that increases the chances of being overweight or obese, but there may be a cure.
Experts from the University of Exeter found that people with a faulty gene called SMIM1 burn less energy while resting, putting them at a huge disadvantage when trying to maintain a healthy weight.
On average, women with this condition are 10 pounds (4.6 kg) heavier and men have an extra 5 pounds (2.4 kg) of fat.
The defect is found in people with a rare blood type called Vel-negative, which is thought to affect around one in 5,000 people.
Women with the SMIM1 genetic deficiency weigh 10 pounds (4.6 kg) more on average, and men have an extra 5 pounds (2.4 kg) of fat.
People with this condition burn less energy while resting, which puts them at a huge disadvantage when trying to maintain a healthy weight.
They are more likely to be obese and overweight, but researchers believe there may be an answer.
It is hoped that a cheap and widely available drug for thyroid dysfunction called levothyroxine may help obesity with SMIM1 gene deficiency.
Professor of cell biology Mattia Frontini, from the University of Exeter Medical School, said: “Obesity rates have almost tripled in the last 50 years and, by 2030, more than a billion people in everyone will be obese.
‘The associated diseases and complications create a significant economic burden on healthcare systems.
«Obesity is due to an imbalance between energy intake and expenditure, often a complex interaction of genetic, environmental and lifestyle factors.
‘In a small minority of people, obesity is caused by genetic variants. When this is the case, sometimes new treatments can be found that benefit these people.
‘We now hope to conduct a clinical trial to find out whether a widely available thyroid supplement drug can be beneficial in treating people who lack SMIM1.
“Our findings highlight the need to investigate the genetic cause of obesity, to select the most appropriate and effective treatment, but also to reduce the social stigma associated with it.”
The proportion of Britons who are overweight or obese has slowly increased over time, reaching two-thirds in 2021, the latest data available. No data was recorded for 2020, the year of the Covid pandemic.
Obesity affects around a quarter of all adults in the UK and increases the risk of diseases such as type 2 diabetes, stroke and coronary heart disease.
The new research, published in the journal Med, was funded by the National Institute for Health and Care Research and the British Heart Foundation.
The team analyzed genetic data from nearly 500,000 individuals and identified 104 people with the variant that leads to loss of function in the SMIM1 gene.
Using blood samples from Vel-negative and positive individuals, they also established that people with SMIM1 deficiency often have other obesity-related conditions.
These include high levels of blood fat, signs of fatty tissue dysfunction, increased liver enzymes, and lower levels of thyroid hormones.
The collaboration included researchers from the University of Cambridge, the Sanger Institute, the University of Copenhagen in Denmark and Lund University in Sweden.
Jill Storry, from Lund University, said: “SMIM1 was discovered only a decade ago, as a highly sought-after blood group protein in red blood cells, but its other function has remained unknown until now.
“It’s very exciting to discover that it plays a more general role in human metabolism.”
Professor Ole Pedersen, from the University of Copenhagen, Denmark, said: “The whole team is looking forward to seeing how this new knowledge can be translated into practical solutions for people with this genetic makeup.”
Dr Luca Stefanucci, from Cambridge, said: “With the increased availability of genetic data and more information about the SMIM1 mechanism, we would like to see that when individuals lacking SMIM1 are identified, they receive information and support.”