Causes of undifferentiated connective tissue dysplasia

Undifferentiated connective tissue dysplasia is a multifactorial disease, most often associated with an anomaly of collagen or other connective tissue proteins (elastin, fibrillin, collagenases). 42 genes participate in the synthesis of 27 types of collagen, more than 1300 mutations have been described in 23 of them. The variety of mutations and their phenotypic manifestations complicates diagnostics. Given the wide representation of connective tissue in the body, this group of disorders often complicates the course of diseases of organs and systems. The skin, musculoskeletal system, heart valves, all layers of the esophagus wall (except for the epithelium) are of mesenchymal origin. Preschool and primary school age are distinguished as critical periods for the formation of connective tissue insufficiency. The main target organs are the skin, musculoskeletal system, cardiovascular, nervous systems. The degree of changes in the internal organs is closely dependent on the number of external manifestations of UCTD.

Undifferentiated connective tissue dysplasia is a genetically heterogeneous group that serves as the basis for the formation of various chronic diseases. There are acquired forms that arise as a result of the influence of various unfavorable factors on the fetus during its intrauterine development. Pedigree data indicate the accumulation of such pathologies in families of sick children as osteochondrosis, osteoarthrosis, varicose veins, hemorrhoids, etc. Many phenotypic signs of DCT and microanomalies have been identified, which can be divided into external, detected during physical examination, and internal, that is, damage to the central nervous system and organ pathology. Prognostic factors of the genealogical history for the formation of DCT are the presence of signs in relatives of the 1st and 2nd degree and sibs of chest deformity, mitral valve prolapse, joint hypermobility, skin hyperextensibility, spinal pathology, myopia. Antenatal criteria for an unfavorable prognosis: maternal age over 30 years, unfavorable pregnancy course, acute maternal illnesses in the first trimester.

Undifferentiated connective tissue dysplasia is diagnosed in cases where the patient's set of phenotypic features does not fit into any of the differentiated syndromes. The cause is considered to be multifactorial effects on the fetus during intrauterine development, capable of causing defects in the genetic apparatus. Differentiation of such connective tissue structures as the spine, skin, heart valves, large vessels occurs at the same time of fetal development, therefore, a combination of dysplastic changes in these systems is most likely.

Undifferentiated connective tissue dysplasia plays a major etiologic role in the development of neurocirculatory dysfunction. According to our data, about a third of children examined for neurocirculatory dysfunction have a complex of CTD signs. The initial background for its development is weakness of the subendothelial layer of blood vessels, developmental anomalies and weakening of the ligamentous apparatus of the vertebrae; due to this, hemorrhages and injuries of the cervical spine are common during childbirth. Juvenile osteochondrosis and high growth rate during puberty increase blood supply disorders in the vertebrobasilar basin. The frequency of allergic diseases is high, among which bronchial asthma prevails.

[ 1 ], [ 2 ], [ 3 ], [ 4 ]