Description of Ehlers-Danlos Syndrome
Ehlers-Danlos Syndrome (EDS) is a group of genetically inherited diseases that involve soft connective tissue by disrupting the production of normal collagen. Ehlers-Danlos syndrome is characterized by the fragility of soft tissue and widespread manifestations in skin, ligaments, joints, blood vessels, and internal organs.
Current classification recognizes six main subtypes:
- Kyphoscoliosis or ocular
There are several new variants discovered in recent years that have not yet been included.
The pathogenesis of EDS comes from mutations in genes linked to collagen encoding or enzymes involved in post-translational processing of collagen proteins. These proteins form components of a large family of extracellular matrix proteins that provide structure and strength to all tissues and organs within the body. Fibrillar collagen form molecules of three intertwined collagen chains. Mutations in type V collagen cause the classic EDS, mutations in type III collagen manifest as vascular EDS, and mutations in type I collagen can lead to the kyphoscoliosis, arthrochalais, or dermatosparaxis types of EDS. Hypermobility EDS, for which most orthopaedics issues arise, has not been identified to result from one particular collagen type.
Symptoms of Ehlers-Danlos Syndrome
Clinically, the spectrum varies from mild skin and joint hyperlaxity to severe physical disability to life-threatening vascular problems. Skin hyperlaxity is one of the most typical features (stretches easily but snaps back after release). The skin is often smooth and velvety in texture. The vascular form of Ehlers-Danlos syndrome is more commonly presents with translucent, thin skin with a prominent venous pattern as opposed to hyperlaxity. The skin is usually fragile and splits easily after minor trauma (especially over pressure points) and shows widened, atrophic scars.
Joint hypermobility is generalized and can be assessed using the Beighton score. It often varies in severity based on age and can become a serious orthopaedic complication due to repetitive subluxations, sprains, and chronic joint pain. In children, muscle hypotonia can present as a delay in motor development. Easy bruising is another very common manifestation, along with a tendency for pronounced bleeding (e.g. following brushing of teeth), even in the presence of normal coagulation studies.