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EHLERS DANLOS SYNDROME CAUSES |
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Ehlers Danlos Syndrome is caused by a defect in one of the
genes involved in collagen production. Some types of Ehlers Danlos Syndrome are known
to be related to a genetic flaw because of the observed inherited
pattern, but the exact defect may not be identified. Classification of Ehlers Danlos Syndrome types was revised in 1997. The new classification is simpler and based more on descriptions of the actual symptoms. Ehlers Danlos Syndrome is now classified into six major types: classical, hypermobility, vascular, kyphoscoliosis, arthrochalasia, and dermatosparaxis, and a collection of rare or poorly defined varieties. Classical type Under the old classification system, Ehlers Danlos Syndrome classical type was divided into two separate types: type I and type II. The major symptoms involve the skin and joints. The skin has a smooth, velvety texture and bruises easily. Individuals with classical type Ehlers Danlos Syndrome typically have extensive scarring at pressure points such as the knees, elbows, forehead, and chin. Owing to loose joints, individuals are at substantial risk for slowed motor development, poor muscle tone, sprains, and partial or complete joint dislocations. Children may have a tendency to develop hernias or other organ shifts within the abdomen. Ehlers Danlos Syndrome classical type is inherited in an autosomal dominant manner. Hypermobility type Excessively loose joints are the hallmark of this Ehlers Danlos Syndrome type, formerly known as Ehlers Danlos Syndrome type III. Both large joints, such as the elbows and knees, and small joints, such as toes and fingers, are affected. Partial and total joint dislocations are common, and particularly involve the jaw, knee, and shoulder. Many individuals experience chronic limb and joint pain, although x rays are normal. The skin may also bruise easily. Ehlers Danlos Syndrome hypermobility type is inherited in an autosomal dominant manner. Vascular type Formerly called Ehlers Danlos Syndrome type IV, Ehlers Danlos Syndrome vascular type carries the risk of premature death. The connective tissue in the intestines, arteries, and uterus is unusually weak, leading to a strong possibility of organ or blood vessel rupture. Such ruptures are more likely between ages 20–40, although they can occur any time, and can be life-threatening. The large joints have normal stability, but small joints in the hands and feet are loose. The skin is thin and translucent, with veins dramatically visible. The skin bruises easily. Other complications can include collapsed lungs, premature aging of the skin on the hands and feet, formation of openings between arteries and veins, and complications following surgery. Ehlers Danlos Syndrome vascular type is inherited in an autosomal dominant manner. Kyphoscoliosis type The major symptoms of kyphoscoliosis type, formerly called Ehlers Danlos Syndrome type VI, are general joint looseness. At birth, the muscle tone is poor, and motor skill development is delayed. Also, infants with this type of Ehlers Danlos Syndrome have an abnormal curvature of the spine (scoliosis). The scoliosis becomes progressively worse with age to the point that the individual may no longer be able to walk by age 20. The eye and skin are fragile and easily damaged, and blood vessel involvement is a possibility. The bones may also be affected as demonstrated by a decreased amount of bone tissue. Kyphoscoliosis type is inherited in an autosomal recessive manner. Arthrochalasia type Dislocation of the hip joint typically accompanies arthrochalasia type Ehlers Danlos Syndrome, formerly called Ehlers Danlos Syndrome type VIIB. Other joints are also unusually loose, leading to recurrent partial and total dislocations. The skin has a high degree of stretchability and bruises easily. Individuals with this type of Ehlers Danlos Syndrome may also experience mildly diminished bone mass, scoliosis, and poor muscle tone. Arthrochalasia type is inherited in an autosomal dominant manner. Dermatosparaxis type Individuals with this type of Ehlers Danlos Syndrome, once called type VIIC, have extremely fragile skin that bruises easily but does not scar excessively. The skin is soft and may sag, leading to an aged appearance even in young adults. Individuals may also experience hernias. Dermatospraraxis type is inherited in an autosomal recessive manner. Other types Certain Ehlers Danlos Syndrome types have retained their original classifications owing to their rarity and a lack of complete information. |
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| EHLERS DANLOS SYNDROME RELATED ITEMS | ||
