I feel brain-fogged. It's a cruelly deceptive illness At the other end of the spectrum are patients who suffer constant pain, stiffness, fractures and dislocated joints, as well as a range of associated complications, from autonomic nervous system disorders to panic attacks. Despite the severity of joint hypermobility syndrome, also known as Ehlers-Danlos Syndrome Type III (EDS), the condition remains widely unknown, and it is often many years before it is diagnosed. Knight hopes a forthcoming storyline in Coronation Street - in which the character Izzy Armstrong, a wheelchair-bound sufferer of EDS, becomes pregnant - may help spread awareness. "It's a cruelly deceptive illness," explains Knight, who works as a clinical administration manager. When doctors examine you and ask you to do stretches, hypermobility means that you look really good - even better than non-hypermobile people. As a result, patients are often dismissed. In the beginning, friends don't understand. Even your family struggles to work out why you're in pain all the time. This year, the Hypermobility Syndrome Association (HMSA), a charity run by and for people with joint hypermobility, celebrates its 20th anniversary. After dealing with the condition for two decades, experts and sufferers have joined forces to call for wider recognition of its causes, symptoms and treatment. Their plea coincides with the launch last month of Britain's first National Institute of Dance Medicine and Science, which aims to coordinate research into dancers" health care and afflictions such as joint hypermobility. "Many professionals still do not acknowledge that this complex multi-systemic condition has such a huge impact on people," says Donna Wicks, senior medical liaison officer at the HMSA. It's horrifying that over 56 per cent of people take longer than 10 years for a diagnosis. In my case, it was 20-odd years. For my mum, it was 37 years, and my grandmother has never been formally diagnosed. Wicks says medical professionals who do appreciate the difficulties of EDS often have to fight to improve services for patients. There are currently only three specialist clinics for EDS in the UK (at University College Hospital in London, the Royal National Hospital for Rheumatic Diseases in Bath and the Glasgow Royal Infirmary), which are overwhelmed with referrals. We have a rehab service at the Royal National Orthopaedic Hospital in Middlesex, but that is also oversubscribed. Knight first noticed she might be hypermobile when she had coordination problems as a child. "If we were doing sports day at school, I'd look as if I was going to go for England and then trip over after about two metres," she remembers. She broke her leg at the age of seven and suffered a series of severe calf cramps, which she believes were due to a micro‑tear in the joint. After years of physiotherapy and inconclusive medical tests, joint hypermobility syndrome was confirmed in 2009. By this stage, Knight was in so much pain that she had given up dancing eight years previously. "I became very lonely and depressed," she says. It was like I was treading a wheel and for every step forward I'd go back three. Howard Bird, a professor of rheumatology at Leeds University, diagnosed Knight after watching her dance. He said I'd got bony hips and shoulders from my maternal grandmother, and the connective tissue side of things from my father. Indeed, EDS is often an inherited disease: research shows around three quarters of sufferers have a family history of the condition. It is also associated with shallow hip or shoulder sockets, weak ligaments, poor muscle tone (the more relaxed muscles are, the greater the range of movement) and proprioception, which is a lack of awareness of joint position and a tendency to over-stretch. Hypermobility is caused by changes in the structure of collagen, a type of protein in the body's connective tissue, which supports other tissues and organs thoughout the body. If collagen is formed differently because of a genetic mutation, the body's moving parts - joints, muscles, tendons and ligaments - become fragile and vulnerable to injury and overstretching. A series of tests, called the Beighton criteria, is used to diagnose joint hypermobility. This involves scoring patients on a number of activities, including placing flat hands on the floor with straight legs, bending knees backwards and twisting fingers backwards past 90 degrees. As well as flexibility, other symptoms include joint instability, subluxation (the ability to dislocate and re-inset a joint), early-onset osteoarthritis, susceptibility to whiplash and childhood "growing pains." Treatment for joint hypermobility syndrome includes physiotherapy, hydrotherapy or low-impact exercise and anti-inflammatory medication. Cognitive behavioural therapy can help manage long-term chronic pain, while splints and supports are often used to combat physical disability. But, says Dr Alan Hakim, consultant rheumatologist and acute physician at Barts Health NHS Trust, its complex symptoms mean that EDS is often confused with other painful conditions such as fibromyalgia. "We need to get better at exploring combinations of treatments," he explains. About 60 per cent of patients I surveyed recently described themselves as in better control of their condition following therapy, which is important as many otherwise describe years of gradual deterioration. The more general practitioners, therapists and the public can be made aware of the condition, the better. After 30 years of coping with hypermobility, Knight is finally beginning to understand her condition - but she refuses to let it get in the way of her daily life. As well as teaching, she is qualified in Bowen therapy (gentle soft tissue massage), and has recently started writing her second book. "I feel great - I've even started jogging, which was an absolute first," she enthuses. And what about dancing? It will always be my passion, even though it's a mixed blessing. After giving up for eight years, it was difficult to get into it again. But it's come flooding back. I hope I will still be dancing when I'm an old lady. Nothing will stop me doing what I love. A Guide to Living With Hypermobility Syndrome" by Isobel Knight (Singing Dragon) is available to order from Telegraph Books at £11.99 + £1.35 p&p. To order, call 0844 871 1515 or visit books.telegraph.co.uk.