Ehlers-Danlos syndrome. Dangers of the vascular type of the syndrome

      Ehlers Syndrome – Danlos is a heterogeneous hereditary disease with different types of inheritance, in which a mutation occurs in the gene responsible for collagen synthesis. As a result, there is no collagen in the connective tissue of the human body. This manifests itself, depending on the type of syndrome, by hyperextensibility of joints, skin, a tendency to hemorrhages, excessive skin vulnerability, and tissue fragility.

For the first time the syndrome was described in the middle of the 17th century by a Dutch surgeon. The symptoms of the syndrome were described in detail at the beginning of the 20th century by scientists E. Ehlers  and H. A. Danlos, after whom the syndrome was named.

Ehlers-Danlos syndrome symptoms. Types of ED syndrome depending on inheritance and manifestations

10 types of the syndrome have been identified, which are different in terms of the symptoms of the syndrome and are considered independent diseases from a clinical and genetic point of view.

• 1 type of ED syndrome is the classic severe type. Occurs with a frequency of 43% of the total number of symptoms of the syndrome. This type is inherited in an autosomal dominant manner. Characteristic symptoms – increased skin elasticity, which is almost 3 times higher than normal, generalized joint hypermobility, increased skin vulnerability. There are deformations of the skeleton in the form of kyphosis and scoliosis. In patients, wounds quickly form, which heal very poorly and slowly, and bleed.
• 2 type is the classic type with a mild course of the ED syndrome. It manifests itself with the same symptoms as type 1, but in a less pronounced form and has a milder course.
• 3 type is called hypermobile and has a benign course. It is inherited in an autosomal dominant manner. The main symptoms of – increased joint mobility and musculoskeletal deformities.
• 4 type is called vascular. This type of syndrome is rare, has a very severe course. It is inherited both dominantly and recessively. The skin is not significantly increased elasticity. Only the joints of the hands are hypermobile. The main clinical manifestation of type 4 syndrome is hemorrhagic syndrome. Such patients are prone to the frequent formation of hematomas and ecchymosis, which can also be in the internal organs. Accompanied by rupture of hollow organs and vessels. This type of syndrome has a high mortality rate.
• 5 type is inherited X-linked recessively. It is characterized by mobility of the joints, increased bleeding and vulnerability of the skin, its extensibility.
• 6 type is called kyphoscoliotic and is inherited in an autosomal recessive manner. It has the same manifestations as type 5, but severe kyphoscoliosis, clubfoot, and muscle hypotension are also observed. Characteristic for the manifestation of type 6 syndrome are eye disorders – keratoconus, glaucoma, retinal detachment, myopia, strabismus.
The
• 7 type is called arthroclasia and is inherited in an autosomal dominant fashion. The main symptoms of this type of syndrome are short stature and frequent dislocations due to increased joint mobility.
• 8 type – inherited in an autosomal dominant manner and is characterized by skin fragility and severe periodontitis, which often leads to tooth loss.
• 9 type is also called X-linked flaccid skin variant, excluded from classification.
• 10 type is inherited in an autosomal recessive manner. It is characterized by hypermobility of the joints, striae on the skin due to atrophy, impaired platelet aggregation.
• 11 type – has an autosomal dominant mode of inheritance. It is characterized by frequent dislocations.

Causes of connective tissue dysplasia in Ehlers-Danlos syndrome

The causes of ED syndrome are biochemical and molecular disorders in the gene responsible for collagen synthesis. It is known that type 1 is characterized by a decrease in fibroblast activity, an increased activity of proteoglycan synthesis, and the absence of enzymes that are responsible for collagen biosynthesis. But the syndrome of type 4 ED (vascular) is due to insufficient synthesis of type 3 collagen. With type 6 syndrome, there are disturbances in the production of the enzyme lysylhydroxylase, which takes part in the hydroxylation of lysine in procollagen molecules. In type 7, there is a violation of the conversion of type 1 procollagen to collagen.

Consequences of connective tissue dysplasia. Danger of the vascular type of syndrome ED.

In the presence of this syndrome, the vessels of the skin, joints and internal organs do not have the elasticity that is needed to maintain homeostasis. With an increase in pressure, an increase in the volume of circulating blood, a sharp spasm during stress, sudden changes in temperature, there is a very high risk of rupture of blood vessels with the formation of hemorrhages and hemangiomas. In the presence of a process in the vessels of the brain, a hemorrhagic stroke develops. Hemorrhages can also form in other important organs, such as the heart, kidneys, liver.

ED syndrome manifests itself already in childhood, when wounds heal poorly after injuries, increased joint mobility is observed. Such children need a gentle regimen, avoidance of any injuries, a protein diet and symptomatic therapy.

At this stage, geneticists can detect pathology already during pregnancy. Therefore, if similar symptoms were observed in the family, it is necessary to consult a geneticist before pregnancy to determine the likelihood of the syndrome in the unborn child.