Landmark DNA study of 3,000 people to unlock mystery of type 2 diabetes

From The Times – Mark Henderson, Science Editor
January 5, 2010

The genetic roots of type 2 diabetes are to be explored in unprecedented depth to help to find better ways to diagnose and treat a disease that affects more than 2 million people in Britain.

Type 2 diabetes, characterised by insulin resistance, can cause blindness and impotence

A £15 million study is to read the complete DNA of 3,000 people, more than ten times more than have so far had their genomes sequenced, The Times has learnt.

The research will provide insight into the biology of type 2 diabetes that can be exploited to develop new ways to treat and prevent the disorder, which can cause kidney and artery disease, blindness and impotence.

The Anglo-American project is the first in a new wave of studies using sophisticated methods of reading DNA that have only recently become affordable. The studies will investigate the influence of DNA onother conditions, such as heart disease, stroke and cancer.

“We are moving genomic research into a new phase,” said Mark McCarthy, Professor of Diabetes at the University of Oxford, who is leading the British side of the type 2 study. “We will be able to pin down many more genetic effects on disease, to understand the biology more completely and give the pharmaceutical industry new targets for drugs.”

Scientists currently hunt for links between DNA and disease by comparing snapshots of the genomes of patients with particular conditions and healthy control subjects. This approach has revealed hundreds of DNA variations that affect disease, including about three dozen linked to type 2 diabetes, but these explain only a fraction of the heritable factors known to play a part.

Much of this “missing heritability” is thought to be caused by variations that are too rare to be found by current techniques. To find these, scientists need to compare the entire genomes of patients and control subjects. However, this has always been prohibitively expensive.

A few years ago the cost of sequencing the thousands of individuals required for useful research would have been more than $1 billion.

The development of new sequencing technology has brought the cost down so sharply that each of the 3,000 genomes required for the research will now cost £5,000.

“This simply isn’t something we could have contemplated until now,” Professor McCarthy said.

Researchers will sequence the entire genomes of 1,500 people with type 2 diabetes and 1,500 people without the disease, then compare the results to look for variations that are significantly more common in the disease group.

The approach should pick up all the genetic variants carried by at least 1 in 100 people that affect the disease. The work should be complete by the middle of 2011.

DNAWellnessinfo.com Resource:  http://www.timesonline.co.uk/tol/news/science/genetics/article6975829.ece