Hypermobile EDS and hypermobility spectrum disorders
Hypermobile Ehlers-Danlos syndrome (hEDS), which used to be known as the hypermobility type or type 3, is thought to be the most common genetic connective tissue disorder. There is no up-to-date research to tell us exactly how frequently it occurs. It can be inherited from a parent with the same faulty gene, alternatively someone can be born with a new mutation so that the condition is occuring in their family for the first time.
Recently some changes were made to the way hypermobile Ehlers-Danlos syndrome is diagnosed. There is no test for hEDS, so diagnosis involves looking for joint hypermobility, signs of faulty connective tissue throughout the body (e.g. skin features, hernias, prolapses), a family history of the condition, and musculoskeletal problems (e.g. long-term pain, dislocations). There are many associated symptoms and disorders which don’t form part of the formal criteria, and which do not directly result from joint hypermobility, for instance orthostatic tachycardia, digestive disorders, pelvic and bladder dysfunction, and anxiety disorders. These are often more detrimental to quality of life than the joint symptoms.
Many people do not fully meet the new diagnostic criteria for hEDS but their hypermobility still causes problems for them. They may experience pain and dislocations, have a poor sense of where their joints are without looking, be prone to injury, have curvature of the spine, and degenerative joint and bone disease. These people may also have many of the non-musculoskeletal disorders associated with hEDS, but they do not quite ‘qualify’ for hEDS. After other possible conditions are excluded, a diagnosis of generalised hypermobility spectrum disorder may be made here.
Joint hypermobility with its possible complications is now classified using the idea of a spectrum. At one end is simple hypermobility which causes no symptoms, is not a disease and is a trait, like height. At the other end of our spectrum is hEDS, and in between falls a range of hypermobility-related conditions called hypermobility spectrum disorders (HSD).
Four subtypes of HSD are distinguished according to which joints are involved, whether the hypermobility is generalised throughout the whole body, and whether other musculoskeletal problems are present. It is also possible to have been hypermobile in the past and to have gradually become stiffer with age, but still have the musculosketal issues associated with that historical hypermobility.
HSD are likely to be common. Someone with HSD can be just as symptomatic, more so even, than someone with hEDS. Management advice for both hEDS and HSD is the same.
Video: The genetics behind connective tissue
Dr Clair Francomano, Clinical Geneticist and Director of Adult Genetics, Harvey Institute of Human Genetics, Greater Baltimore Medical Center, USA
The genetics behind connective tissue, heritable disorders of connective tissue and the different types of EDS.
Video: Hypermobility EDS – an update
Professor Rodney Grahame, Consultant Rheumatologist, The Hypermobility Unit, Hospital of St John and St Elizabeth, London
What we know about the most common type of Ehlers-Danlos syndrome.