Benign Joint Hypermobility Syndrome (BJHS) and Ehlers-Danlos Syndrome (EDS)
Benign joint hypermobility syndrome (BJHS) is the presence of musculoskeletal complaints in hypermobile individuals who do not have a systemic rheumatologic disease. BJHS is thought to be the result of an abnormality in collagen, and mutations in the fibrillin gene have also been identified. The syndrome is often inherited, as first-degree relatives with the disorder can be identified in around 50% of cases.
The most common symptoms felt in people with BJHS are joint hypermobility and joint pain (arthralgia). When joints are excessively loose, it can cause abnormal wear and tear on joint surfaces, leading to pain and degeneration of joints over time. Some research suggests that joint proprioception (internal sense of joint position and movement) in people with BJHS can be impaired, and insufficient or incorrect sensory feedback can lead to dysfunctional movement patterns, poor posture, and pain.
When joints are very loose, people must rely on their muscles for stability in posture and movement. So, it is common for people with joint hypermobility to develop chronic muscular tension and to experience muscle spasms.
Ehlers-Danlos syndrome (EDS) is a group of connective tissue disorders that can be inherited. EDS is currently classified into 13 different subtypes. The most common symptoms of EDS include hypermobile joints, thin or hyperelastic (abnormally stretchy) skin, and skin that bruises or scars easily.
Benign hypermobility joint syndrome is thought to be a mild version of hypermobile EDS (hEDS); some researchers suggest that BJHS is on a continuum with hEDS.
Since EDS is a problem with the structure of connective tissue, various symptoms can occur throughout the body—from skin, muscles, tendons, and ligaments to blood vessels, organs, gums, and eyes. And while joint hypermobility can lead to increased muscle tension because of the need for stability, some types of EDS involve muscle hypotonia (abnormally loose muscles). EDS can cause serious, even life-threatening health conditions including cardiovascular problems, organ rupture, and prolapse.
Both BJHS and hEDS are associated with a broad range of stress-related, psychological, behavioral, neurological, somatic, and gastrointestinal conditions, which you can see in the tables below. The occurrence of these conditions along with BJHS and hEDS may be caused by many different factors, including altered body perception, structural differences in emotion processing regions of the brain, and autonomic nervous system dysfunction.
When any of the conditions below are present, patients may be misdiagnosed or their underlying joint hypermobility may go undetected. Due to the broad range of symptoms and conditions related to joint hypermobility, some patients may be seen as being hypochondriacs. As always, it is important to be your own health advocate.