A collection of genetic disorders that involve mutations of the protein collagen. Connective tissues such as collagen, maintain the skin, bones, blood vessels, and many other organs and tissues. All types of Ehlers-Danlos Syndromes can affect the joints and skin. Each type comes with its own set of signs and symptoms, however it is common for symptoms to overlap from one type to another, making genetic testing important if more serious types are suspected. Currently, genetic testing is available for all types except Hypermobility Type (hEDS).

Some common attributes are: easy bruising, elastic and fragile skin, abnormal scarring and overly flexible joints.

There are now thirteen recognized sub-types of EDS:

  • Classical EDS (cEDS)
  • Classical-like EDS (clEDS)
  • Cardiac-valvular EDS (cvEDS)
  • Vascular EDS (vEDS)
  • Hypermobile EDS
  • Arthrochalasia EDS (aEDS)
  • Dermatosparaxis EDS (dEDS)
  • Kyphoscoliotic EDS (kEDS)
  • Brittle Cornea Syndrome (BCS)
  • Spondylodysplastic EDS (spEDS)
  • Musculocontractural EDS (mcEDS)
  • Myopathic EDS (mEDS)
  • Periodontal EDS (pEDS)



Dislocation of the cerebellar tonsils, downward out of the skull; usually measured in mm (millimeters) or cm (centimeters).

  • What originally distinguished a tonsillar ectopia from a Chiari Malformation rested solely on the size of the herniation.
  • Since 3-5% of the population has some degree of tonsillar ectopia (without symptoms), a tonsillar ectopia was defined as being < 5mm and a CM was > 5mm. (The proper position of the tonsils should actually be 3mm above the foramen magnum.)
  • As studies have shown that size IS NOT the biggest factor in evaluating symptomology, they have moved away from this size based standard approach to diagnosing Chiari.