By Kate Kelland
LONDON (Reuters) - Pakistani and Bangladeshi people in London's least healthy boroughs are being asked to provide spit samples and health records to researchers hoping to find genetic clues to why they are disproportionately affected by certain diseases.
The East London Genes and Health project will focus partly on so-called "knock-out" genes -- rare in the general population but more frequent in communities where cousins and other close relatives marry and have children, as is more common in Pakistani and Bangladeshi communities.
The largest community genetics study in the world will recruit 100,000 volunteers from East London, which have substantial South Asian populations.
Researchers leading the study say health signals buried in the data could have a big impact on peoples' health worldwide.
"This is the first time a large-scale genetics study has focused on two distinct ethnic minority groups, with high levels of health concerns in the community and the potential for significant genetic variation," Richard Trembath, a professor at Queen Mary University of London, told reporters at a briefing.
"These findings will play a key role in tackling health inequality locally and in the UK, (and) we hope to reveal crucial information about the link between genetics and common diseases which will have significant international impact."
Studying genetic variation is crucial to improving understanding of the "normal" variation in genes in certain populations, which can then help the diagnosis of inherited rare diseases.
So-called "knock-out genes" occur when a healthy person has two copies -- inherited from both parents -- of a gene that functions differently to the norm.
The team hopes to use these findings to understand how knock-out genes impact health and eventually to help develop new drugs or treatments which block bad genes and enhance good ones.
East London districts -- and their Pakistani and Bangladeshi communities in particular -- are among Britain's least healthy. Life expectancy is lower, rates of heart disease and diabetes are higher and infectious diseases like tuberculosis are far more prevalent than in other more affluent areas.
"Not only do South Asian people have some of the highest rates of poor health in the UK, they are also markedly under-represented in medical research," said David van Heel, the study's co-leader.
"We aim to change this by gathering a unique dataset which will then be harnessed ... locally, nationally and internationally."
The team will look specifically at heart disease and diabetes and also examine why people of certain ethnicities suffer poor responses to some medicines.