Ehlers-Danlos syndrome is a group of disorders that affect the connective tissues that support the skin, bones, blood vessels, and many other organs and tissues. Defects in connective tissues cause the signs and symptoms of Ehlers-Danlos syndrome, which vary from mildly loose joints to life-threatening complications.
Previously, there were more than 10 recognized types of Ehlers-Danlos syndrome, differentiated by Roman numerals. In 1997, researchers proposed a simpler classification that reduced the number of major types to six and gave them descriptive names: the classical type (formerly types I and II), the hypermobility type (formerly type III), the vascular type (formerly type IV), the kyphoscoliosis type (formerly type VIA), the arthrochalasia type (formerly types VIIA and VIIB), and the dermatosparaxis type (formerly type VIIC). This six-type classification, known as the Villefranche nomenclature, is still commonly used. The types are distinguished by their signs and symptoms, their underlying genetic causes, and their patterns of inheritance. Since 1997, several additional forms of the condition have been described. These additional forms appear to be rare, affecting a small number of families, and most have not been well characterized.
Although all types of Ehlers-Danlos syndrome affect the joints and skin, additional features vary by type. An unusually large range of joint movement (hypermobility) occurs with most forms of Ehlers-Danlos syndrome, particularly the hypermobility type. Infants with hypermobile joints often have weak muscle tone, which can delay the development of motor skills such as sitting, standing, and walking. The loose joints are unstable and prone to dislocation and chronic pain. Hypermobility and dislocations of both hips at birth are characteristic features in infants with the arthrochalasia type of Ehlers-Danlos syndrome.
Many people with Ehlers-Danlos syndrome have soft, velvety skin that is highly stretchy (elastic) and fragile. Affected individuals tend to bruise easily, and some types of the condition also cause abnormal scarring. People with the classical form of Ehlers-Danlos syndrome experience wounds that split open with little bleeding and leave scars that widen over time to create characteristic "cigarette paper" scars. The dermatosparaxis type of the disorder is characterized by skin that sags and wrinkles. Extra (redundant) folds of skin may be present as affected children get older.
Some forms of Ehlers-Danlos syndrome, notably the vascular type and to a lesser extent the kyphoscoliosis and classical types, can involve serious and potentially life-threatening complications due to unpredictable tearing (rupture) of blood vessels. This rupture can cause internal bleeding, stroke, and shock. The vascular type of Ehlers-Danlos syndrome is also associated with an increased risk of organ rupture, including tearing of the intestine and rupture of the uterus (womb) during pregnancy. People with the kyphoscoliosis form of Ehlers-Danlos syndrome experience severe, progressive curvature of the spine that can interfere with breathing.
Although it is difficult to estimate the overall frequency of Ehlers-Danlos syndrome, the combined prevalence of all types of this condition may be about 1 in 5,000 individuals worldwide. The hypermobility and classical forms are most common; the hypermobility type may affect as many as 1 in 10,000 to 15,000 people, while the classical type probably occurs in 1 in 20,000 to 40,000 people.
Other forms of Ehlers-Danlos syndrome are very rare. About 30 cases of the arthrochalasia type and about 60 cases of the kyphoscoliosis type have been reported worldwide. About a dozen infants and children with the dermatosparaxis type have been described. The vascular type is also rare; estimates vary widely, but the condition may affect about 1 in 250,000 people.
Mutations in more than a dozen genes have been found to cause Ehlers-Danlos syndrome. The classical type results most often from mutations in either the COL5A1 gene or the COL5A2 gene. Mutations in the TNXB gene have been found in a very small percentage of cases of the hypermobility type (although in most cases, the cause of this type is unknown). The vascular type results from mutations in the COL3A1 gene. PLOD1 gene mutations cause the kyphoscoliosis type. Mutations in the COL1A1 gene or the COL1A2 gene result in the arthrochalasia type. The dermatosparaxis type is caused by mutations in the ADAMTS2 gene. The other, less well-characterized forms of Ehlers-Danlos syndrome result from mutations in other genes, some of which have not been identified.
Some of the genes associated with Ehlers-Danlos syndrome, including COL1A1, COL1A2, COL3A1, COL5A1, and COL5A2, provide instructions for making pieces of several different types of collagen. These pieces assemble to form mature collagen molecules that give structure and strength to connective tissues throughout the body. Other genes, including ADAMTS2, PLOD1, and TNXB, provide instructions for making proteins that process or interact with collagen. Mutations that cause the different forms of Ehlers-Danlos syndrome disrupt the production or processing of collagen, preventing these molecules from being assembled properly. These defects weaken connective tissues in the skin, bones, and other parts of the body, resulting in the characteristic features of this condition.
The inheritance pattern of Ehlers-Danlos syndrome varies by type. The arthrochalasia, classical, hypermobility, and vascular forms of the disorder have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new (sporadic) gene mutations and occur in people with no history of the disorder in their family.
The dermatosparaxis and kyphoscoliosis types of Ehlers-Danlos syndrome, as well as some of the rare, less well-characterized types of the disorder, are inherited in an autosomal recessive pattern. In autosomal recessive inheritance, two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.
These resources address the diagnosis or management of Ehlers-Danlos syndrome:
These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:
- Ehlers Danlos disease
- Ehlers-Danlos syndrome
- Ehlers-Danlos syndrome, arthrochalasia type
- Ehlers-Danlos syndrome, classic type
- Ehlers-Danlos syndrome, dermatosparaxis type
- Ehlers-Danlos syndrome, hypermobility type
- Ehlers-Danlos syndrome, kyphoscoliosis type
- Ehlers-Danlos syndrome, progeroid type
- Ehlers-Danlos syndrome, vascular type
- Disease InfoSearch: Ehlers-Danlos syndrome
- MalaCards: ehlers-danlos syndrome
- Merck Manual Consumer Version
- My46 Trait Profile: Ehlers-Danlos Syndrome - Vascular Type
- Orphanet: Ehlers-Danlos syndrome due to tenascin-X deficiency
- Orphanet: Ehlers-Danlos syndrome type 11
- Orphanet: Ehlers-Danlos syndrome with periventricular heterotopia
- Orphanet: Ehlers-Danlos syndrome, arthrochalasis type
- Orphanet: Ehlers-Danlos syndrome, cardiac valvular type
- Orphanet: Ehlers-Danlos syndrome, classic type
- Orphanet: Ehlers-Danlos syndrome, dermatosparaxis type
- Orphanet: Ehlers-Danlos syndrome, fibronectinemic type
- Orphanet: Ehlers-Danlos syndrome, hypermobility type
- Orphanet: Ehlers-Danlos syndrome, kyphoscoliotic and deafness type
- Orphanet: Ehlers-Danlos syndrome, kyphoscoliotic type
- Orphanet: Ehlers-Danlos syndrome, musculocontractural type
- Orphanet: Ehlers-Danlos syndrome, periodontitis type
- Orphanet: Ehlers-Danlos syndrome, progeroid type
- Orphanet: Ehlers-Danlos syndrome, spondylocheirodysplastic type
- Orphanet: Ehlers-Danlos syndrome, vascular-like type
- Orphanet: Ehlers-Danlos syndrome, vascular type
- Orphanet: X-linked Ehlers-Danlos syndrome
- Ehlers-Danlos syndrome
- Ehlers-Danlos syndrome Beasley Cohen type
- Ehlers-Danlos syndrome dysfibronectinemic type
- Ehlers-Danlos syndrome progeroid type
- Ehlers-Danlos syndrome type 7, autosomal recessive
- Ehlers-danlos syndrome with progressive kyphoscoliosis, myopathy, and hearing loss
- Ehlers-Danlos syndrome, autosomal recessive, cardiac valvular form
- Ehlers-Danlos syndrome, classic type
- Ehlers-Danlos syndrome, familial joint laxity type
- Ehlers-Danlos syndrome, hydroxylysine-deficient
- Ehlers-Danlos syndrome, musculocontractural type
- Ehlers-Danlos syndrome, musculocontractural type 2
- Ehlers-Danlos syndrome, procollagen proteinase deficient
- Ehlers-Danlos syndrome, progeroid type, 2
- Ehlers-Danlos syndrome, type 2 atypical
- Ehlers-Danlos syndrome, type 3
- Ehlers-Danlos syndrome, type 4
- Ehlers-Danlos syndrome, type 4 variant
- Ehlers-Danlos syndrome, type 5
- Ehlers-Danlos syndrome, type 7A
- Ehlers-Danlos syndrome, type 7B
- Ehlers-Danlos syndrome, type 8
- Ehlers-Danlos syndrome, unspecified autosomal dominant
- EHLERS-DANLOS SYNDROME DUE TO TENASCIN-X DEFICIENCY
- EHLERS-DANLOS SYNDROME WITH PLATELET DYSFUNCTION FROM FIBRONECTIN ABNORMALITY
- EHLERS-DANLOS SYNDROME WITH PROGRESSIVE KYPHOSCOLIOSIS, MYOPATHY, AND HEARING LOSS
- EHLERS-DANLOS SYNDROME WITH SHORT STATURE AND LIMB ANOMALIES
- EHLERS-DANLOS SYNDROME, AUTOSOMAL DOMINANT, TYPE UNSPECIFIED
- EHLERS-DANLOS SYNDROME, AUTOSOMAL RECESSIVE, CARDIAC VALVULAR FORM
- EHLERS-DANLOS SYNDROME, BEASLEY-COHEN TYPE
- EHLERS-DANLOS SYNDROME, CLASSIC TYPE
- EHLERS-DANLOS SYNDROME, HYPERMOBILITY TYPE
- EHLERS-DANLOS SYNDROME, MUSCULOCONTRACTURAL TYPE 1
- EHLERS-DANLOS SYNDROME, MUSCULOCONTRACTURAL TYPE 2
- EHLERS-DANLOS SYNDROME, PROGEROID TYPE, 2
- EHLERS-DANLOS SYNDROME, TYPE IV, AUTOSOMAL DOMINANT
- EHLERS-DANLOS SYNDROME, TYPE V
- EHLERS-DANLOS SYNDROME, TYPE VI
- EHLERS-DANLOS SYNDROME, TYPE VII, AUTOSOMAL DOMINANT
- EHLERS-DANLOS SYNDROME, TYPE VII, AUTOSOMAL RECESSIVE
- EHLERS-DANLOS SYNDROME, TYPE VIII