Search for a twin solution to matters of life and death

A database of 300,000 pairs of twins that would be by far the largest in the world is being planned by British scientists to investigate the genetic and environmental origins of disease and behaviour, The Times has learnt.

Twins in Britain will be invited to join the resource under proposals drawn up by researchers at King’s College London who want to exploit the way that twins provide an “ideal natural experiment” for science.

The £20 million TwinBank project would allow scientists to compare identical and non-identical twins on a scale that has previously been impossible, to extract the relative contributions of nature and nurture to human development. It promises to transform research into common conditions such as obesity, heart disease, autism, mental illness and cancer, as well as shedding light on attributes such as personality and intelligence.

TwinBank would be ten times larger than the biggest twin samples previously assembled, allowing scientists to study many more diseases and traits.

The initiative, devised by Robert Plomin, Professor of Behavioural Genetics, and Tim Spector, Professor of Genetic Epidemiology, has already won the backing of the NHS, which is organising a pilot study.

The scientists are now seeking full funding for the registry, which would cost between £6 million and £20 million, depending on its eventual size and the type of data it includes.

“TwinBank would give us unprecedented opportunities to study the genetic and environmental factors that influence human health and behaviour,” Professor Plomin said. “It would be a dream resource.”

Professor Spector added: “A registry on this scale would give us the ability to study diseases that cannot be investigated through twin research at the moment.”

Twin studies have long been understood as among the best means of assessing how genes and the environment combine to shape the body and mind.

Identical twins share all their DNA, while fraternal twins share only about half – they are no more closely related on a genetic level than ordinary siblings. Both kinds of twins, however, share a womb, a family and cultural environment.

Comparisons between the two types can therefore be used to investigate the importance of heritability. If identical twins share a trait more commonly than fraternal sets, it is highly likely to have a genetic component.

The study aims to contact 500,000 of the estimated 640,000 sets of twins in Britain, and to recruit 300,000 of them to the database. The registry would also collect DNA and health data on twins through the NHS.

Data would be held confidentially, and participants could withdraw at any time.

The size of TwinBank would enable twin studies to investigate medical conditions that affect 1 in 100 people or fewer, such as schizophrenia, leukaemia and motor neuron disease. Other applications include investigations of epigenetics, a phenomenon by which genes are switched on and off, and social issues such as parenting, education and the effects of poverty.

The scientists are confident that most of the twins whom they contact will want to take part in the study. “They know that they are special, they are interested in the results,” Professor Plomin said.

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