University of CambridgeWhile increasing rates of adult obesity have been of grave concern over the years, childhood obesity too appears to be on the rise. A novel analysis by scientists at the University of Cambridge reveals new causes of severe obesity in childhood. The experts appear to have found that a key missing segment of DNA may probably lead to severe childhood obesity.

Claimed to be the first study to exhibit that this kind of genetic alteration can cause obesity, the study evaluated approximately 300 children with severe obesity. Each child’s complete genome was scanned to observe for types of mutation called as copy number variants (CNVs). Large chunks of DNA that either duplicate or delete from our genes, scientists are of the opinion hat CNVs could play a significant part in genetic diseases.

Led by Dr Sadaf Farooqi from the University of Cambridge and Dr Matt Hurles from the Wellcome Trust Sanger Institute, the team looked for CNVs that were distinct in children with severe obesity. They then pitted it against 7,000 controls only to find that certain areas of the genome were lost in some patients who were severely obese.

Dr Farooqi commented, “We found that part of chromosome 16 can be deleted in some families, and that people with this deletion have severe obesity from a young age. Our results suggest that one particular gene on chromosome 16 called SH2B1 plays a key role in regulating weight and also in handling blood sugar levels. People with deletions involving this gene had a strong drive to eat and gained weight very easily.”

Dr Matt Hurles added, “This is the first evidence that copy number variants have been linked to a metabolic condition such as obesity. They are already known to cause other disorders such as autism and learning difficulties.”

These findings experts believe may have implications for identifying severe childhood obesity. It may particularly help diagnose cases which could have been misattributed to abuse. It was also observed that certain children who were part of the study had been formally placed on the Social Services ‘at risk’ register. This was supposedly done assuming that the children’s parents had been intentionally overfeeding their children, leading to severe obesity. However, these children no longer feature in the register.

“This study shows that severe obesity is a serious medical issue that deserves scientific investigation,” shares Dr Farooqi. “It adds to the growing weight of evidence that a wide range of genetic variants can produce a strong drive to eat. We hope that this will alter attitudes and practices amongst those with professional responsibility for the health and well-being of children.”

Now identified as a major global public health concern, obesity is augmenting across the world. Over the past 30 years, the occurrence of obesity has been found to be driven by environmental factors. However even genetic play a major role in determining why some people are more likely to gain weight than others.

The study is published in this week’s Nature.