HEREDITARY CONNECTIVE TISSUE DISORDERS: NOMENCLATURE AND DIAGNOSTIC ALGORITHM

Abstract

Hereditary connective tissue disorders (HCTDs) are a genetically and clinically diverse group of diseases, which encompasses common congenital disorders of fibrous connective tissue structures. Out of the whole variety of the clinical manifestations of NCTDs, only differentiated monogenic syndromes with the agreed guidelines for their diagnosis have been long the focus of the medical community’s attention. Many unclassified forms of the pathology (dysplasia phenotypes) have been disregarded while assessing a person’s prognosis and defining treatment policy. With no clear definition of NCTDs or their approved diagnostic algorithm, it is difficult to study their real prevalence in the population, to compare literature data, and to constructively discuss various scientific and practical aspects of this disease. Efforts to systematize individual clinical types of NCTD and to formulate their diagnostic criteria are set forth in the All-Russian Research Society Expert Committee national guidelines approved in 2009 and revised in 2012. The paper gives current views on the nomenclature of NCTDs, considers diagnostic criteria for both classified monogenic syndromes (Marfan's syndrome, Ehlers–Danlos' syndrome, MASS phenotype, primary mitral valve prolapse, joint hypermobility syndrome) and unclassified dysplasia phenotypes (MASS-like phenotype, marfanoid appearance, Ehlers–Danlos-like phenotype, benign joint hypermobility syndrome, unclassified phenotype). The above abnormalities are presented as a continuous list drawn up in the decreasing order of the degree of their clinical manifestations and prognostic value (the phenotypic continuum described by M.J. Glesby and R.E. Pyentz): from monogenic syndromes through dysplasia phenotypes to an unclassified phenotype. Emphasis is laid on the clinical NCTD identification difficulties associated with the lack of specificity of external and visceral markers of connective tissue asthenia and with the certain conventionality of NCTD diagnostic criteria. Debatable problems in the diagnosis and interpretation of the clinical significance of individual NCTDs are represented.