LONDON: The scientists behind this week’s discovery that some people are genetically predisposed to obesity are poised to reveal the genetic secrets behind a series of other serious but common illnesses.

The biggest DNA analysis of whole human genomes will shed light on why some people are more at risk of developing a serious illness. A coalition of 50 groups, including 24 leading human geneticists, has completed a study which in the course of the next year will reveal genetic signposts for heart disease, diabetes, bipolar disorder and hypertension.

The findings will mark the biggest single leap in the understanding of how genes dictate our propensity to get ill, opening the door to a new wave of tailored therapies and tests to predict the likelihood that people will develop a serious illness.

They have also raised fears that people will abdicate responsibility for living healthily if they discover they have the genetic markers for conditions including obesity, hypertension and type II diabetes.

Mark Walport, director of the Wellcome Trust in the UK, which sponsors the programme, said: “This is the first time that anyone has been able to look at genetic variations at this scale — results for some other diseases are as important as those for obesity.”

Genetic tests are currently available for specific genetic disorders, but the Wellcome Trust Case Control Consortium is looking at the milder and multiple genetic variations which combine with environmental factors to give a person an increased risk of developing a disease.

This week Exeter and Oxford Universities revealed a genetic variation responsible for obesity carried by one in six people and documented how having one copy makes you on average 1.2 kilos fatter and two copies three kilos larger than average.

Over the coming months, the consortium will release similarly detailed findings in major journals for eight common illnesses. The researchers have analysed 19,000 DNA samples, which include 2,000 for people who suffer from each of the diseases and a control group of 3,000. Separately, they are examining 15,000 markers for genetic variations relating to another four diseases — breast cancer, autoimmune thyroid disease, multiple sclerosis, and ankylosing spondylitis, a chronic swelling of the joints.

—Dawn/The Guardian News Service