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Ehlers-Danlos Syndrome, Hypermobility Type

Last updated March 19, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Ehlers-Danlos Syndrome, Hypermobility Type is characterized by extreme mobility of both small and large joints, which leads to susceptibility for joint dislocations.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Benign Joint Hypermobility Syndrome
  • Ehlers-Danlos Syndrome Type III
  • Hypermobility Type EDS

What is Ehlers-Danlos Syndrome, Hypermobility Type? (Definition/Background Information)

  • Ehlers-Danlos Syndrome, Hypermobility Type is one of several connective tissue disorders, collectively known as Ehlers-Danlos Syndrome (EDS). The disorder is caused by abnormal collagen formation and function
    • Connective tissue is made up of structural proteins known as collagens and fibroblast cells, which are arranged in rows
    • These tissues connect bone-bone and muscle-bone, and give strength, support, and elasticity to various structures of the body, like skin, joints, and walls of blood vessels
    • There are 3 types of connective tissue, namely, tendons, ligaments and cartilages
  • EDS, Hypermobility Type is characterized by extreme mobility of both small and large joints, which leads to susceptibility for joint dislocations. Other symptoms include loose skin and a tendency to bruise easily. Complications of the disorder include chronic pain, blood vessel rupture, premature arthritis, and damage to internal organs
  • In most cases, the cause of EDS, Hypermobility Type is not known. In some cases, however, the disease is caused by mutation(s) in the TNXB gene. This gene codes for tenascin X, a protein involved in the synthesis of some types of collagen. An abnormal tenascin X leads to disruption in the organization of connective tissue and its function, leading to the disorder
  • The diagnosis of Hypermobility Type Ehlers-Danlos Syndrome is made by conducting a variety of exams including a physical examination, symptom assessment, evaluation of family medical history, collagen typing, and molecular genetic testing to ascertain gene mutations
  • The treatment options for Hypermobility Type EDS involve medications for pain and blood pressure, physical therapy, and surgery to correct bone dislocations. The prognosis depends on the severity of symptoms and overall health of the affected individual. In most cases, individuals have a normal life span. However, owing to instability of joints and chronic musculoskeletal pain, the quality of life can be severely affected
  • Currently, it is not possible to prevent Hypermobility Type Ehlers-Danlos Syndrome, since it is a genetic disorder. However, if there is a family history of this disorder, prospective parents may benefit from getting tested for associated gene mutations and genetic counseling

Who gets Ehlers-Danlos Syndrome, Hypermobility Type? (Age and Sex Distribution)

  • Ehlers-Danlos Syndrome, Hypermobility Type occurs at a frequency of 1:10,000 to 1:15,000
  • Depending on the severity of the condition, symptoms may be present at birth, or manifest later in life. Typically, affected individuals with milder symptoms get diagnosed in adult life
  • The condition is observed worldwide, without geographic, racial, or gender bias

What are the Risk Factors for Ehlers-Danlos Syndrome, Hypermobility Type? (Predisposing Factors)

The risk factors for developing Ehlers-Danlos Syndrome, Hypermobility Type include:

  • A family history of the disorder
  • Having parents, who are close blood relatives (such as first cousins)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Ehlers-Danlos Syndrome, Hypermobility Type? (Etiology)

It is believed that Ehlers-Danlos Syndrome, Hypermobility Type is caused by genetic mutations. In most cases, the exact cause for the disorder is not known. In some cases, however, mutation(s) in the TNXB gene lead to this disorder.

  • The TNXB gene codes for tenascin-X, a protein involved in the synthesis and assembly of some types of collagen. Tenascin-X plays an important role in the organization and structural integrity of connective tissue
  • A mutation in the TNXB gene may lead to a dysfunctional product, resulting in symptoms of Hypermobility Type EDS

The TNXB gene mutations are inherited in an autosomal dominant manner. In this type of inheritance, a single copy of a defective gene in every cell of an individual is sufficient to cause the condition. Typically, one inherits it from an affected parent.

What are the Signs and Symptoms of Ehlers-Danlos Syndrome, Hypermobility Type?

The following are the signs and symptoms of Ehlers-Danlos Syndrome, Hypermobility Type. The type and severity of symptoms may vary between the affected individuals.

  • Presence of loose, elastic skin (the extent of elasticity may vary from one to another); abnormally-thin skin. or smooth “velvety” skin
  • A tendency to bruise easily
  • Abnormal hip bone
  • Loose joints (laxity of joints); overly-flexible joints i.e., a range of joint movement beyond what is normally observed
  • Joint pain; vulnerability to joint dislocations (elbows, shoulder, kneecap, jaw)
  • Myalgia (muscle pain)
  • A tendency to develop early-onset osteoarthritis
  • Thin, fragile blood vessels, may predispose an individual to hemorrhages
  • Fragile internal organs and other tissues
  • Arrhythmia (irregular heartbeat)
  • Sleep disturbances
  • Constipation

How is Ehlers-Danlos Syndrome, Hypermobility Type Diagnosed?

The diagnosis of Ehlers-Danlos Syndrome, Hypermobility Type is undertaken with the help of the following tests and exams:

  • A thorough physical examination and an assessment of symptoms
  • An evaluation of personal and family medical history
  • Measurement of skin hyperextensibilty, by pulling up skin, till resistance is registered
  • Beighton scale hypermobility testing for joints: This operates on a 9-point system; a score of over 6 may indicate hypermobility
  • Collagen typing using a skin biopsy sample
  • Collagen skin mutation testing
  • Electron microscopic observation of a skin sample
  • Imaging tests such as X-ray, computed tomography (CT) scanning, or magnetic resonance imaging (MRI):
    • For checking bone mass
    • For structural abnormalities of the heart, along with echocardiography
  • Genetic testing to confirm mutations in genes that cause EDS, Hypermobility type

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Ehlers-Danlos Syndrome, Hypermobility Type?

Ehlers-Danlos Syndrome, Hypermobility Type can lead to the following complications:

  • Bruising of skin
  • Repeated joint dislocations
  • Early-onset arthritis
  • Chronic muscle pain
  • Delayed wound healing
  • Spontaneous rupture of blood vessels
  • Mitral valve regurgitation (blood flowing back into the heart)
  • Uterine or arterial rupture during pregnancy
  • Premature membrane rupture during pregnancy or rapid labor and delivery

How is Ehlers-Danlos Syndrome, Hypermobility Type Treated?

The treatment for Ehlers-Danlos Syndrome, Hypermobility Type is symptomatic, as there is no cure for the disorder. Often, a coordinated effort by professionals from various specialties may be needed to help the affected individual achieve a certain quality of life:

The following are some measures for treating the symptoms of Hypermobility Type EDS:

  • Medications for pain relief: The strength of medication administered depends on the severity of pain
  • Medications, to reduce blood pressure (necessitated by fragile blood vessels), such as the following:
    • Beta blockers
    • Angiotensin-converting enzyme inhibitors
    • Calcium channel blockers
    • Diuretic pills
  • Proper and balanced nutrition
  • Vitamin C supplements may be recommended to aid in collagen synthesis and wound healing
  • Physiotherapy to strengthen muscles around weak joints
  • Braces to stabilize joints and minimize dislocations
  • Wheelchair use, in case of severe joint instability
  • Rarely, surgery to repair joints damaged by repeated dislocations may be performed, if necessary

How can Ehlers-Danlos Syndrome, Hypermobility Type be Prevented?

Ehlers-Danlos Syndrome, Hypermobility Type is a genetic disorder, and currently, there are no methods or guidelines available to prevent its occurrence.

  • Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
  • If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
  • In individuals who are diagnosed with EDS, Hypermobility Type, the following may be helpful in reducing injuries, dislocations, and bleeding:
    • Avoiding contact sports and other activities that may cause injury
    • Wearing padding over joints that are vulnerable to dislocation
    • Avoiding unnecessary surgical procedures, since wound healing may be compromised
    • If surgery becomes necessary, then taking precautions against bleeding before, during, and after the procedure or surgery
    • Proper counseling and medical care for women before and during pregnancy, as well as during and after childbirth 
  • Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders such as Ehlers-Danlos Syndrome, Hypermobility Type

Regular medical screening at periodic intervals with tests and physical examinations are crucial and are highly recommended.

What is the Prognosis of Ehlers-Danlos Syndrome, Hypermobility Type? (Outcomes/Resolutions)

  • The prognosis of Ehlers-Danlos Syndrome, Hypermobility Type is determined by the severity of the disorder and overall health of the affected individual. The life expectancy of individuals with this disorder is reported to be normal
  • However, chronic pain and joint instability can reduce the quality of life. Often, a lifelong management of the condition with medication, physiotherapy, and other measures is necessary

Additional and Relevant Useful Information for Ehlers-Danlos Syndrome, Hypermobility Type:

Please visit our Congenital & Genetic Disorders Health Center for more physician-approved health information:


What are some Useful Resources for Additional Information?

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Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 7, 2017
Last updated: March 19, 2018