Ehlers Danlos Syndrome (EDS) is a heritable connective tissue disease with six major subtypes. EDS occurs in approximately 1/5000 births. Classical EDS (cEDS) and hypermobility type EDS (HEDS or ht-EDS) are the most common forms, with approximately 90% of patients having one of these types. Vascular EDS (vEDS) affects about 5% of EDS patients. The remaining types are rare. Generally, EDS patients demonstrate hypermobility of joints, excessive stretchiness of the skin (hyperextensibility) and fragility of soft tissues.
Ehlers Danlos is diagnosed by clinical evaluation and diagnostic testing. Mutations affecting structure of collagen, a key component of connective tissue, have been identified for cEDS and vEDS. For hypermobility type EDS, no consistent genetic anomality has been found. As a result, diagnosis of this subtype relies upon patient history and clinical examination.
The Beighton scale is a nine point scale for evaluating hypermobility. One point is granted for each: elbow hyperextended more than 10°, knee hyperextended more than 10°, thumb that can be touched to the forearm, and fifth finger that can be passively bent back more than 90°. One further point is granted for being able to place the palms flat on the floor with knees fully extended. A score of 5 points or more is suggestive of joint hypermobility, a major criterion for diagnosis of HEDS.
In addition to an appropriate Beighton score, soft skin with normal or slight hyperextensibility and absence of significant soft tissue abnormalities are also important for HEDS diagnosis. Excessive skin hyperextensibility and serious fragility of connective tissue could be indicative of other forms of EDS.
Hypermobility type EDS was regarded for many years as a benign laxity of the joints. In recent years, this position has been debunked, though this belief still persists for many medical providers. Hypermobility and musculoskeletal pain were previously recognized as the dominant manifestations, but we now know that HEDS can cause cardiovascular, gastrointestinal, genitourinary and neurologic symptoms, among others. In fact, the aspects of this disease that aren’t musculoskeletal are the most disabling and are correlated with lower quality of life
Symptoms arising from dysfunction of the autonomic nervous system have serious impact on quality of life as demonstrated in a number of conditions, including chronic fatigue syndrome and fibromyalgia. Autonomic dysfunction can be assessed with an Autonomic Symptom Profile (ASP), a questionnaire of 169 questions that evaluates symptoms in eight broad categories: orthostatic (upright posture), secretomotor (secretion of substances by glands), urinary, GI, pupillomotor (movement of the pupil), vasomotor (changing diameter of blood vessels), reflex syncope (dysfunction of blood pressure and heart rate) and sleep function. These functions are all controlled by the autonomic nervous system.
References:
de Wandele I, et al. Dysautonomia and its underlying mechanisms in the hypermobility type of Ehlers-Danlos syndrome. Seminars in Arthritis and Rheumatism 2014, 44: 93-100.
de Wandele I, et al. Autonomic symptom burden in the hypermobility type of Ehlers-Danlos syndrome: A comparative study with two other EDS types, fibromyalgia, and healthy controls. Seminars in Arthritis and Rheumatism 2014, 44: 353-361.
Wallman D, et al. Ehlers-Danlos Syndrome and Postural Tachycardia Syndrome: A relationship study. Journal of Neurological Sciences 2014, 340: 99-102.