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Genetic mutation could cause weight gain



Scientists from the University of Cambridge found that one in 340 people in the UK carry a genetic mutation linked to weight gain, making the mutation more common than previously thought.

The research which, recently published in NatureMedicine, showed people who carry the mutated gene were more likely to have a greater weight from early childhood. By 18 years of age, they were on average 2.5 stone heavier and the majority of this excess weight was fat.

Currently, over 63% of adults in the UK are above a healthy weight, and one in three schoolchildren leave primary education overweight.

Obesity has a genetic component and a number of genes are linked to weight gain.

This study examined the melanocortin 4 receptor gene (MCR4) which works by producing a protein that sends signals to the brain about how much fat is being stored in the body. If the gene is faulty, the brain assumes low-fat stores and signals to the body that it is starving and needs to eat, leading to excessive weight gain.

The prevalence of the mutated gene was determined from a random sample taken from a database of over 6,000 participants in the Children of the 90s study run by the University of Bristol.

The researchers examined the MCR4 coding sequence in 5,724 participants and characterised all mutated MC4R variants and their function.

Professor Sir Stephen O’Rahilly, from the University of Cambridge and one of the authors of the study, said: ‘Parents of obese children are often blamed for poor parenting and not all children obtain appropriate professional help. Our findings show that weight gain in childhood due to a single gene disorder is not uncommon.’

He added: ‘This should encourage a more compassionate and rational approach to overweight children and their families – including genetic analysis in all seriously obese children.’

It is hoped that the research will also aid in the design of new medicines. A drug that can bypass the signal blockage caused by the MRC4 genetic mutation would enable people to maintain a healthy weight.