This May, in order to spread awareness of EDS, I will be sharing some facts about the condition as layed out in the new diagnostic nosology that was published in March of 2017 in the American Journal of Genetics.
The Ehlers-Danlos Syndromes are a collection of genetic connective tissue disorders that impact the proper formation of collagen in the body. Collagen is sometimes considered the metaphorical “glue” of the body, as it holds together our skin, joints, and organs. Because collagen is found all over the body, EDS manifests itself in many different ways and can cause a variety of symptoms throughout body systems.
The new nosology recognizes 13 types of Ehlers-Danlos Syndrome in addition to the Hypermobility Spectrum Disorders (HSD):
- Classical EDS (cEDS): cEDS is one of the two most commonly diagnosed types of EDS and is recognizable by skin hyperextensibility and/or atrophic scarring in addition to generalized joint hypermobility. Classical EDS is confirmed by mutations in COL5A1 or COL5A2.
- Classical-Like EDS (clEDS): clEDS is recognizable by skin involvement with absense of atrophic scarring, easy bruising, and generalied joint hypermobility. clEDS is confirmed by mutations in TNXB.
- Cardiac Vascular EDS (cvEDS): cvEDS is defined by severe and progressive problems with cardiac valves, skin involvement and either generalized or localized joint hypermobility. It is confirmed by a COL1A2 mutation.
- Vascular EDS (vEDS): vEDS is generally considered the most severe form of EDS, often shortening the lifespan significantly. It is confirmed by a mutation in COL3A1 or COL1A1, and is recognizable by family history or personal experience with arterial rupture at young ages, spontaneous organ rupture, uterine rupture during third trimester in absence of prevoius c-sections, and formation of cartoid-cavernous sinus fistulas.
- Hypermobile EDS (hEDS): hEDS is the most commonly diagnosed form of EDS, and the only remaining form for which a molecular/genetic basis has not yet been identified. This is the type of EDS that I have. The diagnosis is made clinically, and is based on the presence of mild skin involvement (soft skin, but generally not as extensible as in cEDS or clEDS), generalized joint hypermobility, and widespread chronic musculo-skeletal pain.
- Arthrocholosia EDS (aEDS): aEDS is identiifed by mutations in COL1A1 or COL1A2 that cause an entire or parital loss of exon 6. Major critieria for the identification aEDS include congenital bilateral hip dislocation, severe generalized joint hypermobility with multiple dislocations and subluxations, and skin involvement. aEDS is considered to be one of the rarer types of EDS.
- Dermatosparaxis EDS (dEDS): dEDS is caused by a mutation in ADAMTS2. Some of its features include extreme skin fragility and characteristic craniofacial features. dEDS is considered to be one of the rarer types of EDS.
- Kyphoscoliotic EDS (kEDS): kEDS is caused by a mutation in PLOD1. kEDS is recognizable by low muscle tone, the presence of congenital or early onset kyphoscoliosis, and generalized joint hypermobility. The knees, hips, and shoulders seem to be most effected kEDS. kEDS is considered to be on eof the rarer types of EDS.
- Brittle Cornea Syndrome (BCS): BCS is most often caused by mutations in either ZNF469 or PRDM5. The major criteria for a diagnosis are thin cornea (with or without rupture), early onset and progressive keratoconus and keratoglobus, and blue sclerae. It is considered to be one of the rarer types of EDS.
- Spondylodysplastic EDS (spEDS): spEDS is another rare type of EDS. It is caused by a mutation in B4GALT7, B3GALT6, or SLC39A13. spEDS is characterized by short stature, bowing of limbs, and low tone.
- Musculocontractural EDS (mcEDS): mcEDS is also a rare type of EDS, and is characterized by congential contractures including clubfoot, characteristic facial features, and skin involvement. It is most often caused by mutations to CHST14.
- Myopathic EDS (mEDS): Myopathic EDS (mEDS) is characterized by low muscle tone and/or muscle atrophy, hypermobility of small/distal joints, and congenital joint contractures. It is identified by a mutation in COL12A1. It is also considered another of the rarer types of EDS.
- Periodontal EDS (pEDS): pEDS is another of the rare types of EDS, and is caused by mutations to C1R or C1S. It is recognizable by family history, severe and early onset gum disease, and lack of attached gums, and pretibial plaques (leg ulcers).