Causes
The cause of the disease is a genetic defect. A change (mutation) in the genes that describe the structural protein collagen on the human genome, the DNA, occurs. The mutation leads to an altered structure and/or reduced synthesis of collagen, which results in a reduced strength of the entire connective tissue. Types I and II are a mutation in the gene collagen V, while type IV is a mutation in collagen III.
Symptoms
Due to the disturbed and reduced collagen synthesis, Ehlers-Danlos syndrome affects those parts of the body that are particularly rich in connective tissue: the skin, joints and blood vessels. Since the connective tissue lacks strength, it is overstretchable and tears very quickly, which can lead to small and sometimes massive bleeding, especially in blood vessels. An important complication is the formation of aneurysms with the risk of rupture.
The main symptom of the skin is the pronounced cutis hyperelastica, which can be lifted up to 4cm or more at the sides of the neck, over joints and also in the face. After letting go, it immediately springs back into its original position, which is why it is also called “rubber skin”. In general, the skin is noticeably thin (like cigarette paper), soft and velvety (“marshmallow skin”).
Wounds show delayed wound healing, so that sutures take 3 to 4 times longer to heal. Atrophic or hypertrophic, inferior scars often develop from the sutures. In addition, fluid-filled (succulent) bulges of the skin (molluscoid pseudotumors) are formed in areas of the body subject to heavy strain, such as the knee and elbow joints, and knuckle pads on the backs of the hands and feet and nodules on the heel.
The joints are hyperextensible (hyperflexibility), often move in unintended directions and lack strength due to loosened joint ligaments (ligament laxity). As a result, unusual movements can be performed, as known from “contortionists”. The joints tend to dislocate (luxations) and malpositions.
Especially the shoulder and ankle joints, the patella, the temporomandibular joint (temporo-mandibular joint) and less frequently the elbow joint are affected.The documentation of joint hypermobility is based on the Beighton score, which confirms hypermobility with 5 out of 9 possible points. Further symptoms of joints are generalized joint pain, chronic neck pain, back and hip pain, joint and muscle pain that is difficult to treat. Sometimes pain points (“tender ponits”) can also be identified, which are defined as an area that reacts painfully to pressure loads of 4 kg or less.
In addition, there is an increased risk of fracture due to reduced bone mass combined with an abnormal bone structure. Due to the fragility of the connective tissue of the blood vessels, there is a pronounced tendency to hematomas, spontaneously or as a result of trauma, mainly in areas at risk of injury. This is followed by a typical brown pigmentation in the affected areas.
After injuries,a tendency to prolonged bleeding with normal coagulation values is observed. The fragility of larger blood vessels can lead to massive, life-threatening bleeding triggered by exertion, accidents, pregnancy or birth. Since other connective tissue structures are also inferior, it can lead to hernias (hernias/hernia), spinal curvature (scoliosis), ruptures (rupture) of the intestine and uterus (uterus), aneurysms of blood vessels and constriction of the lungs due to free air in the chest (pneumothorax). In rare cases, eye changes such as astigmatism or glaucoma are observed in connection with EDS.
