What is Ehlers-Danlos Syndrome (EDS)

Please note: This post was updated on 5/18/20.

It’s Ehlers-Danlos Syndrome Awareness Month and time for an updated post which describes the symptoms and attributes of EDS. The Ehlers-Danlos Syndromes are a group of genetic connective tissue disorders that affects the body’s ability to produce strong, healthy collagen. As a result, people with EDS usually have hypermobile joints and some types include hyper-extensible skin, but these are only a couple of the most easily recognized symptoms of the Ehlers-Danlos Syndromes. The reality is that EDS has the ability to affect any and all parts of the body in a wide variety of ways that often seem strange and enigmatic to those ignorant of the condition.

The most common forms of EDS include Classical, Vascular and Hypermobile EDS. Hypermobile EDS is by far the most commonly diagnosed and is the only form of EDS for which the genetic marker has not yet been discovered. While each of these conditions have features that are specific to that type alone, there are some things which are fairly universal about Ehlers-Danlos Syndrome, such as our hypermobile joints.

EDS’s 13 Subtypes and Their Symptoms

 In 2017, the Ehlers-Danlos Society worked with an international panel of experts to update EDS classification and better define the criteria for diagnosis. As of the 2017 diagnostic criteria changes, there are now 13 distinct subtypes of Ehlers-Danlos Syndrome:

  1. Classical EDS (cEDS)
  2. Classical-like EDS (clEDS)
  3. Cardiac-valvular EDS (cvEDS)
  4. Vascular EDS (vEDS)
  5. Hypermobile EDS
  6. Arthrochalasia EDS (aEDS)
  7. Dermatosparaxis EDS (dEDS)
  8. Kyphoscoliotic EDS (kEDS)
  9. Brittle Cornea Syndrome (BCS)
  10. Spondylodysplastic EDS (spEDS)
  11. Musculocontractural EDS (mcEDS)
  12. Myopathic EDS (mEDS)
  13. Periodontal EDS (pEDS)

Update: Recently, a 14th type was discovered, however it has yet to be classified. On last report, only 4 people had been identified with what may be an extremely rare autosomal recessive type involving the AEBP1 gene.

The most common forms of EDS include Classical, Vascular and Hypermobile EDS. Hypermobile EDS is by far the most commonly diagnosed and is the only form of EDS for which the genetic marker has not yet been discovered. While each of these conditions have features that are specific to that type alone, there are some things which are fairly universal about Ehlers-Danlos Syndrome, such as our hypermobile joints. Hypermobile joints are loose and to dislocate or subluxate (a quick dislocation which pops back in on its own) easily. This has a tendency to cause recurrent soft tissue damage, the formation of osteoarthritis and other joint issues. Many people with EDS need multiple joint rehabilitation, replacements and surgeries throughout their lifetimes.

Because spines are a string of small bones and joints separated by thick discs comprised of collagen, zebras are also prone toward scoliosis, degenerative disc disease at young ages, spinal stenosis, ankylosing spondilitis, craniocervical instability and chiari malformations, among many other spinal conditions. I had my first herniated disc at 19 and was refused imaging for over 10 years because the doctors insisted I was “too young to have that problem.”

Our joints are only a small part of the picture when it comes to EDS. Because the body is comprised of more than 80% collagen, EDS can strike anywhere in the body. There is collagen in our blood, our bones, our hair, skin, muscles, organs, and other connective tissues. It is often described as the glue which holds our bodies together, but it’s really so much more. Here’s a list of the many symptoms and comorbid conditions known to occur as part of Ehlers-Danlos Syndrome:  fb_img_1470755630970.jpgfb_img_1470755778226.jpgfb_img_1470755915319.jpgfb_img_1470755925911.jpg

As you can see from this vast list of common symptoms and complications, it is easy for an EDS zebra to be diagnosed with dozens of conditions, disorders and syndromes throughout their lifetime. Currently, I have nearly twenty diagnoses and I am still working on finding doctors capable of diagnosing and treating other existing problems.

The Issues of Diagnosis of Ehlers-Danlos Syndrome

As I stated earlier, the most common forms include Classical, Vascular and Hypermobile Ehlers-Danlos Syndrome. hEDS is by far the most diagnosed, but this may be due in part to the fact that it is often diagnosed clinically (without genetic testing) and is the most well-known form. Since the genetic marker for hEDS has not yet been discovered (unlike other forms) and genetic testing can be expensive and difficult to obtain in both public and private healthcare systems, these issues may also play a factor in the prevalence of this diagnosis compared to other subtypes. When it comes to the diagnosis of any form of EDS, it is understood among patients and EDS specialitss alike that EDS is massively underdiagnosed and/or misdiagnosed.

While I became symptomatic as a teen, I was not diagnosed until the age of 44, despite having Hypermobility and many other clear cut signs. I wasn’t shy about going to specialists and seeking answers, either. Time to diagnosis often ranges from 7-14 years after the onset of symptoms. This is the reason zebras are used as a symbol for EDS and other rare diseases; to encourage doctors to sometimes think zebras instead of horses when “hearing the hoof beats” of connective tissue and autoimmune disease. In medical school, doctors are encouraged to do the opposite and assume every patient has something common and easier to address.

Lack of knowledge on the part of the physician is also highly problematic. While I live in a fairly large American metropolitan city and saw dozens of doctors, none of them could tell me what I was suffering from. I actually had to discover the diagnosis for myself, judge myself against the criterion and spend over a year trying to find a doctor with enough experience to diagnose me. Cincinnati has a geneticist who can diagnose EDS, but they don’t take adults and I know for a fact his waiting list is a year long. Ultimately, I was diagnosed by a rheumatologist who did a fantastic evaluation, but refused to take me on as a patient due to the complexity of the condition. I am by no means alone in this.

In Canada, I hear frequent stories of possible EDSers being turned away from the only places that can diagnose them because they’re simply overwhelmed with patients and choosing not to help those whose care may not seem as critical to their survival. What that means is that millions of us go undiagnosed, untreated and suffer needlessly for years on end without assistance or hope of intervention.

While EDS is more prevalent in women than men, it is a genetic disorder that anyone can get, regardless of sex, ethnicity or race. Just as fickle as its lack of discrimination is how it affects the individual. How I experience EDS is different than how it affected my own mother. While some of this is dependent on the development of comorbidities, even when those match, ability levels and complications can be vastly different. If you have a loved one with EDS it’s very important to understand this and not expect them to be like Mary who happens to have the same condition.  Understanding this makes organizations which deny patients aid based on subtype rather than individual need seem pretty ridiculous and downright cruel.

How Diagnosis is Made

For those who do find a doctor qualified to diagnose their condition, there are clear-cut criteria one must meet for diagnosis. These parameter changed in 2017 along with the condition types. Of all 13 subtypes, only one cannot be confirmed via genetic testing. While genetic testing is the preferred method of diagnosis, there simply aren’t enough geneticists to handle current needs in any country, so it is sometimes left to a strictly clinical diagnosis using the international criteria and the Beighton Score.

“For those who meet the minimal clinical requirements for an EDS subtype—but who have no access to molecular confirmation; or whose genetic testing shows one (or more) gene variants of uncertain significance in the genes identified for one of the EDS subtypes; or in whom no causative variants are identified in any of the EDS-subtype-specific genes—a “provisional clinical diagnosis” of an EDS subtype can be made. These patients should be followed clinically, but alternative diagnoses and expanded molecular testing should be considered.” (The Ehlers-Danlos Society)

The international criterion differ based on subtype, but there are many similarities. To get an idea of what’s required, the criteria for hEDS is as follows:

The diagnosis of hypermobile EDS (hEDS) remains clinical; there is no molecular, genetic cause yet identified, so there is no test available for almost all with hEDS.

There is a clinical spectrum ranging from asymptomatic joint hypermobility, through “non-syndromic” hypermobility with secondary manifestations, to hEDS.

A diagnosis of hEDS should be assigned only in those who meet all of the criteria, which should help research efforts to discover the underlying genetic cause(s) which, in turn, may help clinical management. As this is a clinical diagnosis, it’s important to be relatively confident that the diagnosis is not instead one of the many other disorders of connective tissue. Hypermobile EDS is inherited in the autosomal dominant pattern.

The clinical diagnosis of hEDS needs the simultaneous presence of criteria 1 and 2 and 3. This is a complex set of criteria, and there is much more detail than presented in this overview; please see the page for hypermobile EDS.

  1. Generalized joint hypermobility (GJH); and
  2. Two or more of the following features must be present (A & B, A & C, B & C, or A & B & C):

            Feature A—systemic manifestations of a more generalized connective tissue disorder (a total of five out of twelve must be present)

            Feature B—positive family history, with one or more first degree relatives independently meeting the current diagnostic criteria for hEDS

            Feature C—musculoskeletal complications (must have at least one of three); and

  1. All these prerequisites must be met: absence of unusual skin fragility, exclusion of other heritable and acquired connective tissue disorders including autoimmune rheumatologic conditions, and exclusion of alternative diagnoses that may also include joint hypermobility by means of hypotonia and/or connective tissue laxity.

There is a range of conditions which can accompany hEDS, although there is not enough data for them to become diagnostic criteria. While they’re associated with hEDS, they’re not proven to be the result of hEDS and they’re not specific enough to be criteria for diagnosis. Some of these include sleep disturbance, fatigue, postural orthostatic tachycardia, functional gastrointestinal disorders, dysautonomia, anxiety, and depression. These conditions may be more debilitating the joint symptoms; they often impair daily life, and they should be considered and treated (The Ehlers-Danlos Society).

For the full criterion for all 13 subtypes, visit the Ehlers-Danlos Society

To better understand these criterion, here are the criteria broken down by section:

hEDS Criterion 1 for Diagnosis
hEDS criterion 2 for diagnosis
hEDS criterion 3 for diagnosis

The graphic below explains which joints are checked for Hypermobility during examination. Note that the Beighton is based ONLY on the joints shown. In order to meet the criteria, children need 6 or greater, adults under 50 need 5 or greater, and anyone over 50 must have 4 or more, as we lose our Hypermobility to arthritis and other conditions along the way. 


It’s important to understand that while we’re flexible, hyperextending our joints can have disastrous results. It’s easy to tear our delicate tissues, which rarely heals correctly afterward and tend to worsen with age.

Our joints are only a small part of the picture when it comes to EDS. Because the body is comprised of more than 80% collagen, EDS can strike anywhere in the body. There is collagen in our blood, our bones, our hair, skin, muscles, organs, and other connective tissues.

If you suspect you may have EDS, it’s important to get diagnosed, even if you haven’t started experiencing symptoms until later in life. Hormonal changes, such as puberty and menopause, often trigger symptoms, as does illness, injury or physical or emotional trauma, creating wild fluctuations in the typical age of onset. EDS zebras need to protect their joints by modifying exercise and other activities, eat whole organic foods and care for their bodies in special ways.

To find out more about how to care for your Ehlers-Danlos body, a good place to start is our Health & Wellness Section!

References and Additional Reading Materials:

11 thoughts on “What is Ehlers-Danlos Syndrome (EDS)

  1. Hi Tamara! Thanks so much for taking the time to learn about EDS! I looked up your condition, as I’m not very familiar with it. If you ever want to write about it, let’s talk. I’m always happy to bring awareness and understanding of any chronic condition. Thanks so much for reading!


  2. 13 subtypes is very eye-opening. Before blogging and meeting lots of incredible people in the blogosphere, I knew very little about EDS, and it’s people like you who make all the difference. Very thorough post, you did amazingly covering it in a way that’s easy to understand.
    Caz xx


  3. Just so you know, the 2019 comes up in first line of the intro before you click on the post, so it’s not on the actual post but possibly happened when you updated it.


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