Double vision: The twins who are helping scientists to discover more than 400 novel genes associated with over 30 diseases

One twin remarked it was a nice change to wear the same clothes as the other after a lifetime spent trying to look different. Another told a story about having the same illness as her twin which lasted for the same duration – despite the pair being on different continents and unaware the other was ill.

But after the six sets of twins who came together for today’s TwinsUK’s “coming of age” celebrations had traded ice-breaking anecdotes, talk turned to the pleasure they have felt in giving to a greater cause.

They are among 6,000 sets of twins who have donated their time and bodies to the Department of Twin Research (DTR) at King’s College, London, to help what the professor heading up the unit describes as “an unprecedented two decades” of research.

From diabetes to arthritis, short-sightedness to cancer, the research has allowed scientists to discover more than 400 novel genes associated with more than 30 diseases. Today, the unit, Based at St Thomas’ Hospital, London, was celebrating the fruits of that 21 years of genetic research which has unravelled answers to all manner of health conditions and helped develop drugs to treat them.

Those advances have allowed doctors to start to unravel the secrets of epigenetics – the “switches” which make genes develop into a disease – with the hope that one day we will be able to “turn off” cancerous genes.

“It is a great feeling, to know that you are helping others by developing research,” says Janese Samuels, 53, from Tooting, south London, who has been part of the DTR programme for 15 years. “Some people give their bodies to medical research when they die, we get to do it when we are alive.”

Hazel Green from West Chiltington, West Sussex, says the DTR is like a family with added benefits.

“You have complete piece of mind. By definition you are constantly tested and these results go to our GP,” she says, “but it’s for everyone, it’s just they can use us to get the results.”

Professor Tim Spector, director of TwinsUK at King’s College London, has been working on the project since the beginning in 1992 when he and a staff of two – there are now 55 – tried to get 400 twins to be part of a study into arthritis.

“This is a huge milestone for us and represents a coming of age landmark. We have published over 600 scientific papers using the data we have collected,” he says. “TwinsUK is one of the largest twin registries in the world. The participation and commitment of the twins over the years has made a huge difference to our scientific knowledge of many common diseases.”

The unit has come a long way from those early days when twins would fill in questionnaires to help researchers study conditions like osteoporosis.

“When we started a lot of these things were not fashionable science. Everyone thought [the conditions] were due to old age and they were inevitable,” he says. “But we showed these things were due in part to genetics and we paid them more attention ... it helped re-focus doctors’ minds on common age-related problems.”

Buoyed by early success, and funded by The Wellcome Trust and the National Institute for Health Research (NIHR) Biomedical Research Centre, the unit grew and strengthened which, Professor Spector says, eventually allowed the advent of genome-wide association studies that mapped the whole DNA of twins to identify genes influencing the risk of disease.

As a direct result of this kind of work there are now four different anti-leukaemia drugs on the market that work epigenetically.

“Twins are perfect for studying epigenetics as we can clearly see that being born with the same genes does not mean they experience the same health throughout their lives,” Professor Spector says. “Why does one twin develop diabetes or heart disease and the other does not for example.”

The department has more than 300 twins who have breast cancer, and 30 pairs of twins have already been studied where one had breast cancer and the other didn’t – even though both had a predisposition to it. “We are looking at why something happened, perhaps through lifestyle, that allowed this switch to happen,” he says. “The idea is if we can detail changes five-years before cancer we can do something about it as epigenomes are reversible and can be turned off.”

The DTR will continue its birthday celebrations tomorrow when hundreds of twins will take part in scientific experiments for research into pain, short-sightedness, hearing loss, skin ageing and even telepathy.

“I am extremely excited about what the future of genetics discovery will hold over the next 21 years, as we move onto an area of personalised medicine,” Professor Spector says. “I can envisage a time when a person’s DNA will be taken at birth and measured repeatedly for epigenetic changes so medicines can be tailored to that individual.”

Twin power

Margaret Micklewright and Rosemary Case, from Ruislip, aged 80

Margaret: “We started 21 years ago, and were numbers 61 and 62. We’ve had all sorts of tests.”

Hazel Green from West Sussex, and Christine Dafter from Kent, aged 68

Hazel “All the girls from the south east go to London together and we make a day of it.”

Margaret Turton from Eastbourne and Barbara Pilgrim from Redhill, aged 54

Barbara “It’s nice to feel you are contributing to research.”

Janet Morgan and Janese Samuels, from Tooting, aged 53

Janese “We will keep helping until we are old and can’t do it anymore”

Rebecca and Zoe Fearnley, 44, from Hackney, aged 44

Zoe “It makes you feel like you have contributed to something, you are part of it.”

Gemma Hall and Nadine Osman, from Streatham, aged 28

Gemma “It gave us a greater understanding of ourselves”