Ehlers-Danlos syndrome is still called EDS, but the old numbering system (Type I, Type II, Type III, etc.) was replaced in 2017 with descriptive names that reflect each subtype’s primary features. The updated classification, published by an international consortium of researchers, expanded the recognized subtypes from six to 13 and introduced stricter diagnostic criteria, particularly for the most common form.
The Old Numbers vs. the New Names
If you were diagnosed with or read about EDS before 2017, you likely encountered Roman numeral labels. Type I and Type II, for example, are now grouped under Classical EDS (cEDS). Type III is now Hypermobile EDS (hEDS). Type IV, the form involving fragile blood vessels and organs, is now Vascular EDS (vEDS). The new names describe what each subtype actually does to the body rather than relying on an arbitrary number.
The full list of 13 recognized subtypes under the 2017 classification is:
- Classical EDS (cEDS), marked by very stretchy, fragile skin
- Classical-Like EDS (clEDS), similar to classical but with a different genetic cause
- Hypermobile EDS (hEDS), primarily involving joint hypermobility
- Vascular EDS (vEDS), involving fragile arteries, organs, and skin
- Kyphoscoliotic EDS (kEDS), featuring severe muscle weakness and spinal curvature
- Arthrochalasia EDS (aEDS), with severe joint looseness present from birth
- Dermatosparaxis EDS (dEDS), with extremely saggy, fragile skin
- Cardiac-Valvular EDS (cvEDS), primarily affecting heart valves
- Brittle Cornea Syndrome (BCS), affecting the eyes
- Spondylodysplastic EDS (spEDS), involving short stature and skeletal abnormalities
- Musculocontractural EDS (mcEDS), with joint contractures and fragile skin
- Myopathic EDS (mEDS), primarily causing muscle weakness
- Periodontal EDS (pEDS), affecting the gums and teeth
Why the Classification Changed
The old system was created when only a handful of subtypes were recognized and the genetics behind them were poorly understood. As researchers identified the specific gene mutations responsible for different forms of EDS, it became clear that some types needed to be split apart and others needed to be added entirely. The 2017 system ties each subtype (where possible) to its underlying genetic cause, making diagnosis more precise.
For 12 of the 13 subtypes, the responsible gene is now known. Classical EDS, for instance, results from mutations in genes that produce type V collagen. Vascular EDS stems from defects in the gene responsible for type III collagen. Genetic testing can confirm a diagnosis for all 12 of these subtypes. The exception is hEDS: its genetic cause remains unidentified, so it is diagnosed entirely through clinical criteria.
Hypermobile EDS and Hypermobility Spectrum Disorders
The 2017 reclassification hit hardest for people with the hypermobile form, previously called Type III. The new criteria for hEDS are significantly stricter. To qualify, you need generalized joint hypermobility (measured by the Beighton score), plus specific findings in the skin and other body systems, or a confirmed family history. A positive Beighton score is 5 out of 9 for adults and 6 out of 9 for children.
Many people who would have been diagnosed with EDS Type III under the old system no longer meet the hEDS threshold. For those individuals, the 2017 framework created a new category: Hypermobility Spectrum Disorders, or HSD. HSD is not a lesser diagnosis or a dismissal. It applies to people with symptomatic joint hypermobility who don’t fully meet hEDS criteria, often because they have fewer findings in the skin or musculoskeletal system or lack a family history. The symptoms and daily challenges of HSD can be just as significant as those of hEDS.
If your Beighton score falls just one point below the cutoff, clinicians use a five-question screening tool to determine whether you still qualify as having generalized joint hypermobility. People who don’t meet that threshold may still receive an HSD diagnosis if their hypermobility causes pain, instability, or other problems.
Vascular EDS: A Name Change Worth Knowing
The shift from “Type IV” to “Vascular EDS” matters because the new name signals the subtype’s most dangerous feature. vEDS involves fragile arteries, intestines, and (in women) the uterus. Thin, translucent skin and easy bruising are common. Doctors look for four major signs when deciding whether genetic testing is warranted: arterial, intestinal, or uterine rupture or fragility; extensive bruising; thin, see-through skin; and a characteristic facial appearance with thin lips, a narrow nose, and large eyes. Two or more of these features typically prompt a referral for genetic testing to confirm a mutation in the COL3A1 gene.
How Diagnosis Works Under the New System
For every subtype except hEDS, the diagnostic path involves clinical evaluation followed by genetic testing to confirm the specific mutation. This is a shift from the older approach, where many diagnoses rested on clinical judgment alone. If a person meets the clinical criteria for classical EDS, for example, the next step is testing for mutations in the COL5A1 or COL5A2 genes.
For hEDS, because no gene has been identified, diagnosis remains entirely clinical. You must meet a checklist that evaluates joint hypermobility, skin involvement, family history, and the absence of other connective tissue disorders that could explain the symptoms. This can make getting a diagnosis frustrating, since there’s no blood test or genetic panel that gives a definitive yes or no.
Another Update Is Coming in 2026
The 2017 criteria are not the final word. The Ehlers-Danlos Society has announced that a new diagnostic framework will be published on December 1, 2026, in the American Journal of Medical Genetics. Once released, it will replace the current 2017 criteria for all EDS subtypes and HSD. A follow-up publication in March 2027 will outline best-practice care and management pathways. The update draws on systematic literature reviews, international clinical expertise, and a structured consensus process among experts.
If you’re currently navigating a diagnosis, the 2017 system is what clinicians are using right now. But it’s worth knowing that the criteria may shift again, particularly for hEDS and HSD, where the diagnostic boundaries have been the most debated since the last update.