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The recent studies of molecular physiology of fibrillin and pathophysiology of inherent disorders of structure and function of connective tissue such as dissection and aneurysm of aorta, myxomatously altered cusps and prolapses of mitral valve, syndrome of hyper-mobility of joints, demonstrated that important role in development of these malformations play alterations of transfer of signals by growth factors and matrix cellular interaction. These conditions under manifesting Marfan's syndrome can be a consequence of anomalies of fibrillin-1 which deficiency unbrakes process of activation of transforming growth factor-β (TGFβ). The involvement of TGFβ in pathogenesis of Marfan's syndrome permits consider antagonists of angiotensin-transforming enzymes as potential pharmaceuticals in therapy of this disease. The article presents analysis of publications' data related to this problem.

The results of direct DNA diagnostics in nine patients with Marfan syndrome, aged from two to 52 years old, and four unhealthy relatives with the same disease from two unrelated families have been presented for the first time in Russia. Eight mutations in the gene FBN1 were revealed. One patient demonstrated a substitution with unknown clinical importance, which was previously described in the SN P database as rsl 12287730 with a frequency of incidence of 0.1%. Out of the eight mutations, two (25%) were previously described, and the other six mutations (75%) were revealed for the first time. These mutations revealed by us were of the following types: three mutations (37.5%) produced a shift in the open reading frame (two deletions and one insertion), three mutations (12.5%) involved a splicing site, and one (12.5%) nonsense mutation was also noted. Our data contradict previous reports that claimed that the majority of mutations in the FBN1 gene represented missense mutations. Such inconsistency could result from a small size of the examined sample or from substitutions that produced alteration in the splicing site (as we have demonstrated here). The distribution of the revealed mutations was uniform along the whole gene. The results of the conducted comparative analysis of genetic and phenotypic indices was in complete agreement with previously reported results. The developed direct method of DNA diagnostics was fully informative, as we managed in all nine examined patients to confirm their clinical diagnosis using a molecular and genetic approach.

Thoracic aortic aneurism (TAA) develops as a result of complex series of events that dynamically alter the structure and composition of the aortic vascular extracellular matrix (ECM). The main elements that alter the composition of aortic wall are smooth muscle cells (SMC). The purpose of the present work was to study alteration of smooth muscle cell functions derived from the patients with TAA and from healthy donors. As it is supposed that TAA associated with bicuspid aortic valve (BAV) and with tricuspid aortic valve (TAV) differ in their pathogenesis, we compared the SMC and tissues samples from BAV-, TAV-patients and healthy donors. We compared TAA patients' derived tissues and SMC to healthy donors' ones in several parameters: SMC growth, migration and apoptotic dynamics; metalloproteinase MMP2 and MMP9 activity (zymography) and elastin, collagen and fibrillin content (Western blot) in both tissue samples and cultured SMC. Proliferation ability of both BAV and TAV SMC was decreased comparing to donors cells; migration ability in scratch tests was increased in TAV-derived SMC comparing to donor cells. BAV-cells migration ability was not changed comparing to donor-SMC. Elastin content was decreased in TAA SMC comparing to donor cells whereas the content of fibrillin and collagen was not altered. At the same time elastin and collagen protein level was significantly higher in tissue samples of TAA patients comparing to donor-derived samples. SMS proliferation and migration ability is differently affected in TAV and BAV-associated TAA that supports the idea of different nature of these two groups of TAA. Also our data show that SMC functional properties are altered in TAA patients and these alterations could play a significant role in the disease pathogenesis.

Marfan syndrome is a disorder of the connective tissue that is inherited in an autosomal-dominant fashion and that is caused by mutations in the gene coding for fibrillin-1, FBN1. Although complications of the syndrome may involve the eye, the lung and the skeleton, the high mortality of untreated cases results almost exclusively from cardiovascular complications, including aortic dissection, rupture and mitral valve regurgitation. The multiorgan involvement of many of these syndromes requires multidisciplinary expert centers that can increase the average life expectancy of affected patients from only 32 years to over 60 years. The present article both reviews classical standards of managing cardiovascular manifestations and highlights the surgical approach for aortic and mitral valve surgery in Marfan patients.

30 exons have been analyzed using SSCP in patients with MFS or related phenotypes. We report 2 missense mutations occur in calcium-binding Epidermal Growth Factor-like (EGFcb) domains and 9 polymorphisms located both in coding and noncoding regions of FBN1 gene. Three intragenic microsatellite polymorphic markers MTS-1, MTS-2 and MTS-4 have been analyzed in patients with MFS and unrelated unaffected control individuals. We found significant differences in allele frequency distribution of MTS-2 and MTS-4 loci between MFS patients and unaffected individuals. Haplotype frequency distribution on normal and mutant chromosomes were significantly different. The most common haplotype was 2-11-8 which was predominant on normal chromosomes of affected individuals. Haplotype 2-2-8 was observed in 18% of cases on mutant chromosomes and in 4% of cases on normal chromosomes. These data demonstrate possibility and application of haplotype-segregation analysis with use of these intragenic markers for diagnostic purposes in affected families by Marfan's syndrome.