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  Disease summary:

  
  
  
  
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    Ligamentous laxity predisposes to joint instability, subluxations, and dislocations.

    
    
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    Chronic pain and fatigue are common.

    
    
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    The classical type is distinguished from the hypermobility type by the presence of skin fragility, hyperelasticity, and atrophic scarring in the former.

    
    
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    Additional features may include easy bruising, prolonged bleeding, cardiovascular autonomic dysfunction, mild-to-moderate aortic root dilation, and functional bowel disorders.

  
  
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  Hereditary basis:

  
  
  
  
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    Both types of EDS are inherited in an autosomal dominant pattern.

    
    
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    The genetic basis of most cases of hypermobility type EDS is unknown.

    
    
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    Mutations in one of the two genes for type V collagen account for half of cases of classical type EDS.

  
  
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  Differential diagnosis:

  
  
  
  
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    Four other types of EDS are described in Table 169-1.

    
    
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    There are dozens of other genetic causes for ligamentous laxity, including (but not limited to) Marfan syndrome, Loeys-Dietz syndrome, Stickler syndrome, fragile X syndrome, and Turner syndrome.

    
    
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    Hypotonia, which itself is a feature of many genetic conditions, can also cause joint laxity, and may be difficult to distinguish from ligamentous laxity.

Diagnostic Criteria

(see Table 169-2):

Joint laxity is semi objectively measured with the Beighton scale (1 point each for ability to place palms on the floor with knees straight; hyperextension of each elbow or knee >10 degrees; dorsiflexion of each fifth finger >90 degrees; passive apposition of each thumb to flexor surface of forearm). A score of 5 or more is considered positive, but males, older individuals, and those with arthritis and/or history of trauma typically have less laxity, so lower scores may be considered positive.

Skin elasticity is best measured in a location without excess or redundant skin (ie, not the elbow, back of hand, neck, or cheek). The volar wrist is a good option; normal is approximately 1 cm.

Clinical Characteristics

Joint laxity, leading to instability, subluxations, and dislocations is common to all types of Ehlers-Danlos syndrome (EDS) (see Table 169-1). Pain and fatigue, often out of proportion to physical examination and radiologic findings, are frequent and sometimes disabling. Both neuropathic pain and myofascial spasm are likely to occur. Migraines and temporomandibular dysfunction are also common.

Soft skin, prolonged bleeding, and easy bruising are also common to all types of EDS. The classical type is distinguished from the hypermobility type by the presence of skin hyperelasticity and fragility, as well as delayed wound healing, wound dehiscences, and atrophic (“cigarette paper”) scars. Rupture or tearing of arteries, intestines, or uterus are not features of the hypermobility type, and only very rarely occur in the classical type.

Functional bowel disorders, including gastritis and irritable bowel syndrome, affect up to half of EDS patients.

Cardiac autonomic dysfunction, manifesting as neurally mediated hypotension and/or postural orthostatic tachycardia are also common. Mild-to-moderate aortic root dilation occurs in up to one-third of patients. Mitral valve prolapse, using modern diagnostic criteria, is not an associated feature of EDS.