Ehlers-Danlos syndrome

Last revised by Douglas Dunn on 15 Oct 2022

Ehlers-Danlos syndrome comprises a heterogeneous group of collagen disorders (hereditary connective tissue disease).

The combined prevalence for all types of Ehlers-Danlos syndrome is estimated to be at least 1 of every 5000 individuals. There is no significant gender predominance.

Ehlers-Danlos syndrome clinically manifests with

  • skin hyperelasticity and fragility
  • joint hypermobility
  • blood vessel fragility with bleeding diathesis 1
  • poor tissue healing with delayed healing with tissue paper-like scarring 1

There are at least ten subtypes with variable inheritance patterns. The majority are autosomal dominant:

  • types I and II (also called classic Ehlers-Danlos syndrome) are autosomal dominant and result from mutations in COL5A1 and COL5A2 9.
  • type III (also called hypermobility Ehlers-Danlos syndrome) is autosomal dominant with an unknown biochemical origin 9.
  • type IV (also called vascular Ehlers-Danlos syndrome 4) is autosomal dominant and involves the arteries, GI tract, uterus and skin; COL3A1 mutation result in type III collagen production
  • type VI (also called kyphoscoliosis Ehlers-Danlos syndrome 9) is recessively inherited. It results from a mutation in the gene that encodes lysyl hydroxylase
  • type VII is is subclassified into arthrochalasia (type VIIa/b - autosomal dominant) and dermatosparaxis (type VIIc - autosomal recessive) which result from mutations in COL1A1/COL1A2 and procollagen N-peptidase respectively. COL1A1/COL1A2 mutations result in defective conversion of procollagen to collagen 9.
  • types V, VIII, IX and X are very rare and their features have not been fully described 1

The 2017 Ehlers-Danlos classification lists 13 subtypes, including several newly-identified rare forms of the disease 7,8.

The imaging findings of Ehlers-Danlos syndrome are best discussed according to system.

  • multiple ovoid calcifications (<1 cm) in the subcutaneous tissue
  • ectopic ossification 2

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