EDS is a heterogeneous group of disorders that affect connective tissues at different degrees of severity, from mild clinical signs to life-threatening complications.
Confusions have been made at first in clearly defining the different types of EDS. Much of the older literature did not make any difference in them, wrongly considering EDS to be a rather homogeneous disorder. This lack of differentiation between the EDS subtypes had first an impact on clinical management of the disease. Features we now know to be only associated with vEDS tended to be associated to the syndrome as a whole, causing anxiety in patients affected with other types of EDS. Also, it was quite a hurdle in conducting research. As a matter of fact, in addition to lead to different symptomatologies, the different types of EDS actually segregate in different ways and have distinct genetic and molecular features. However, at the same time, finding out the genetic and molecular basis of EDS also helped progress in clarifying the heterogeneity of EDS.
The current nosology of EDS has been established in three major steps, following the progresses made in genetic and molecular understanding of the syndrome.
In 1988, the “Berlin Nosology” portrayed 11 forms of EDS, each of them being characterized by a Roman numeral. This categorization mainly relied on clinical findings and modes of inheritance. vEDS is still often referred as EDS type IV because of this original nomenclature.
Over time, it became apparent that the clinical criteria established in 1988 did not differentiate adequately between the different forms of EDS. In 1997, this nomenclature was re-assessed due to new insights into the genetic and biochemical bases of many of these EDS types. A simpler classification was published by Beighton under the name of the Villefranche nomenclature. The number of EDS types was reduced to six and each of these types received a more descriptive name based on their major features, e.g. vascular EDS.
Finally, in 2017, the nosology was updated by including rare forms of EDS that were discovered more recently. The International EDS Consortium finally recognized 13 types of EDS.
The point of clearly defining the different types of EDS is also to help discriminate them from other phenotypically related disorders such as the Marfan syndrome.
References
Beighton, P. De Paepe, A. Steinmann, B. Tsipouras, P. Wenstrup, R.J. (1998) ‘Ehlers-Danlos syndromes: revised nosology, Villefranche, 1997. Ehlers-Danlos National Foundation (USA) and Ehlers-Danlos Support Group (UK).’, Am J Med Genet. 77(1):31-7.
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Byers, P.H. (1994), ‘Ehlers-Danlos Syndrome: Recent Advances and Current Understanding of the Clinical and Genetic Heterogeneity’. J Invest Dermatol. 103(5 Suppl):47S-52S.
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Medizinische Universität Innsbruck (unknown), Ehlers-Danlos. Available at http://www.p-eds.org/ehlers-danlos/ (Accessed : 18 November 2018)
Laferrier, J.Z. Muldowney, K. Muldowney, K. (2018),‘A Novel Exercise Protocol for Individuals with Ehlers Danlos Syndrome: A Case Report’ J Nov Physiother. 8(2): 382
