Ehlers-Danlos syndromes (EDS) are a group of rare conditions that affect the connective tissue and can be inherited. Connective tissue lies between tissues and organs throughout the body and helps to support them. In EDS, this connective tissue can be more fragile and stretch more.
EDS has undergone repeated changes to its classification. Some early groupings identified eleven forms of EDS, which were labelled using Roman numerals. Then, in 1997, this system was changed to only include six types of EDS, each with its own descriptive name. Over time, several more forms of EDS have been discovered, and in 2017 the classification system expanded to include a total of thirteen subtypes of EDS. Most forms of EDS are now known to be associated with changes to specific genes.
However, it is important to bear in mind that EDS affects people differently, and can produce a diverse range of symptoms. Furthermore, there can be a large amount of overlap in symptoms between EDS subtypes, and also between forms of EDS and other connective tissue disorders. For example, several types of EDS may share symptoms such as joint hypermobility, stretchy skin, and fragile skin (easily bruised or broken), and many people with different types of EDS suffer from long-term pain, fatigue, digestive disorders, dizziness, and palpitations.
According to the NIH, the thirteen forms of EDS combined are estimated to affect at least one in every 5,000 people worldwide. However, lots of patients with EDS have to wait years to reach a diagnosis, and many people think that EDS is under-diagnosed and that the actual prevalence of the condition is likely to be much higher.
The thirteen subtypes of EDS and some (but by no means all) of the symptoms associated with them are briefly outlined below.
1. Hypermobile EDS (hEDS)
Hypermobile EDS is the most common form of EDS. People with hEDS may have conditions including joint hypermobility, frequent bruising, fatigue, and unstable joints, amongst others.
Many people say that hEDS shares significant similarities to, or may be the same as, another condition called joint hypermobility syndrome. This issue is further complicated by changes to the diagnostic criteria for hEDS, and the lack of one identified genetic cause of hEDS. To learn more about the differences between hEDS and joint hypermobility syndrome, you can visit the Ehlers-Danlos Society’s article on it here
2. Classical EDS (cEDS)
Classical EDS can affect the skin more than hEDS. People with cEDS may experience joint hypermobility and instability, stretchy skin, fragile and easily broken skin, and frequent bruising, and a range of other possible symptoms.
3. Classical-like EDS (clEDS)
This form of EDS may be associated with symptoms such as stretchy skin, skin with a ‘velvety’ feel and no atrophic (pitted) scarring, joint hypermobility, and easily bruised skin. It has been linked to the gene TNXBVascular EDS (vEDS)
Vascular EDS is often associated with very serious conditions, including fragile blood vessels are prone to bulging and tearing, resulting in internal bleeding, organ problems, such as bowel or womb tearing and lung collapse
4. Cardiac-Valvular EDS (cvEDS)
This form of EDS may affect the heart (cardiac-valvular problems), skin (stretchiness, bruising, thin skin, atrophic scars), and joints (hypermobility), amongst other possible symptoms.
5. Arthrochalasia EDS (aEDS)
Arthrochalasia EDS has been linked to symptoms including hip dislocation, joint hypermobility, and stretchy skin.
6. Dermatosparaxis EDS (dEDS)
Dermatosparaxis EDS may be suggested by characteristics such as very fragile skin and certain facial features associated with the condition.
7. Kyphoscoliotic EDS (kEDS)
Kyphoscoliotic EDS has been linked to features including congenital (present from birth) decreased muscle tone, kyphoscoliosis (an unusually curved spine), and generalised joint hypermobility.
8. Brittle Cornea Syndrome (bcEDS)
People with brittle cornea syndrome may have thin cornea (a transparent covering on the eye), early-onset keratoconus (when the cornea thins and bulges into a cone shape), early-onset keratoglobus (a thing cornea that takes on a globular shape), and blue sclerae (when the whites of the eyes turn blue), amongst other symptoms.
9. Spondylodysplastic EDS (spEDS)
This form of EDS may be associated with symptoms such as a short stature, bowing of limbs, and reduced muscle tone.
10. Musculocontractural EDS (mcEDS)
Musculocontractural EDS has been linked to congenital (from birth) multiple contractures (permanently shortened muscle or joint), skin features such as easily bruising, stretchiness, fragility, and atrophic scars, and certain facial features, amongst other symptoms.
11. Myopathic EDS (mEDS)
Myopathic EDS causes symptoms that may include congenital reduced muscle tone or muscle atrophy that can improve with age, hypermobile distal joints (joints far from the centre of the body), and proximal joint contractures (such as in the knee, hip, and elbow).
12. Periodontal EDS (pEDS)
Periodontal EDS has been linked to symptoms to do with the teeth, such as severe periodontitis (gum infection) that may begin in childhood or adolescence, a lack of attached gingiva (gums), and other symptoms such as pretibial plaques.
This article is based on source information from The Ehlers-Danlos Society, the NHS, Ehlers-Danlos Support UK, and the NIH. This article provides an overview of EDS, but shouldn’t replace guidance from healthcare professionals.