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Inherited connective tissue disorders are clinically and genetically diverse conditions affecting the skin, joints, and a variety of extracutaneous tissues, including the cardiovascular (CV) system. The nature and severity of the skin phenotype is dependent on the type of mutation as well as the role of the affected protein on dermal structure and function (see Chaps. 15 and 18). The diagnosis of many inherited connective tissue disorders is clinical, although Clinical Laboratory Improvement Amendments (1988) (CLIA)-approved genetic testing is increasingly available. A listing of research laboratories that might offer testing can be found at http://www.genetests.org.
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EHLERS-DANLOS SYNDROMES
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AT-A-GLANCE
Combined incidence of almost 1 in 5000 persons.
Thirteen subtypes.
Most commonly autosomal dominant (classical and hypermobile types).
Defects in the Type V collagen gene most commonly cause the classical subtype.
Cutaneous features include varying degrees of skin fragility and hyperextensibility. The classical subtype exhibits soft, velvety skin that bruises easily and wounds that heal as thin, atrophic, gaping scars.
Extracutaneous manifestations include hypermobile joints with frequent dislocations, complications with pregnancy and delivery, and, less commonly, cardiovascular manifestations, particularly aortic root dilation.
Information for patients and professionals at http://www.ehlers-danlos.org and https://www.ehlers-danlos.com/.
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A variety of genetically and clinically heterogeneous inherited conditions characterized by varying degrees of skin fragility and hyperextensibility, and joint hypermobility have been collected under the rubric of the Ehlers-Danlos syndromes (EDS). A new classification system published in 20171 attempted to consolidate and simplify existing subgroups (Table 72-1) as well as reconcile new genetic discoveries with existing clinical phenotypes. Major and minor diagnostic criteria were developed for each major subtype of EDS. Despite these revisions, many patients defy clear-cut classification. The spectrum of EDS severity ranges from subtle clinical findings to severe, debilitating disease.
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