What is Ehlers-Danlos Syndrome?
EDS is an inherited connective tissue disorder which presents with a wide variety of symptoms which can affect health and quality of life. Joint hypermobility, tissue fragility and pain are common features of EDS.
What Causes EDS?
Changes in collagen protein
Collagen is a protein that provides flexibility and strength to the body tissues. Gene changes cause abnormal production or maturation of collagen in the body which results in Ehlers-Danlos Syndrome. The abnormal gene can come from parents but can also occur for the first time in a person. These gene changes result in the formation of abnormal or weak collagen that is unable to support the body organs and other tissues.
There are 13 types of EDS. Hypermobile EDS (hEDS) is the most common type and is the only type that does not have a genetic mutation identified to cause it. Diagnosis is based on clinical assessment and internationally recognized diagnostic criteria.
The other types of EDS are rare and can be identified with a genetic blood test when the minimal diagnostic criteria is met.
Generalized Hypermobility Spectrum Disorder (G-HSD) falls under the umbrella of EDS and presents with many of the same signs and symptoms as hEDS. There is no genetic mutation known to cause G-HSD.
The Spectrum of Hypermobility
Joint hypermobility is the ability of a joint to move beyond the normal range of motion.
Hypermobility is a genetic trait and exists along a continuum. Hypermobility can be congenital (you are born with it) or acquired (developed over time) and can occur for many different reasons.
Hypermobility is common in children and in many cases decreases as you age. In some cases hypermobility may continue into adulthood. Hypermobility may not lead to any symptoms (asymptomatic) or may lead to pain, instability, early onset osteoarthritis and other musculoskeletal issues.
Joint hypermobility is common in the general population (up to ~30% of population) and can affect 1 to 2 joints (localized joint hypermobility) to multiple joints (generalized joint hypermobility). Joint hypermobility is not always secondary to an underlying connective tissue disorder such as EDS.
Physiotherapy and joint protection is currently the best method of treatment.
How is hypermobility assessed?
Assessment of hypermobility is completed through detailed physical examination by an experienced practitioner.
Hypermobility is not the same as joint instability. Hypermobility is an increased range of motion of the joint, while instability refers to the inability to control joint movement. Joint instability may be the results weakened or injured muscles, bones, nerves or ligaments which weaken the joint causing it to become unstable.
In some cases joint hypermobility may lead to joint instability (dislocation or subluxation), but instability of a joint is not always accompanied by joint hypermobility. This means it is possible to have dislocations or subluxations of joints without having generalized joint hypermobility.
Hypermobility is confirmed through the Beighton score which measures joint hypermobility on a 9-point scale. In order for the Beighton score to be accurate it must be assessed by an experienced practitioner using a goniometer to measure joint range of motion.
The joints assessed on the Beighton score are the base of the pinkies, base of the thumbs, elbows, knees and the lower spine. A positive Beighton score is ≥4/9 in individuals 50 years and older, ≥5/9 in individuals 18-49 and ≥6/9 under age 18. A positive Beighton score, demonstrating generalized joint hypermobility, is required to make a diagnosis of hEDS/G-HSD.
Courtesy of The Ehlers-Danlos Society www.ehlers-danlos.com