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| Author(s): |
Bruno Lazzari de Lima
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB) |
| Defense date: | 2011-03-15 |
| Examining board members: |
Lygia da Veiga Pereira Carramaschi;
Carla Rosenberg;
Mariz Vainzof;
Claudio Chrysostomo Werneck
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| Advisor: | Lygia da Veiga Pereira Carramaschi |
| Abstract | |
The Marfan syndrome (MFS) is an autosomal dominant disease of connective tissue, which affects 1 in 5,000 individuals. The main clinical manifestations include aneurysms and aortic disruption, excessive growth of bones, scoliosis and thoracic deformities. Mutations in the FBN1 gene, which encodes the fibrillin-1 protein, were genetically linked to the MFS, classifying this disease in the fibrilinopathies group. Over 500 mutations have been identified and, except for a small group of recurrent mutations, the mutations are unique, being found in unrelated families. The disease is characterized by a wide clinical variability both within and between families, and it is not possible to make a precise genotypephenotype correlation. This work concerns the analysis of the mechanisms associated with the clinical variability present within and between MFS families, by qualitative and quantitative characterization of the phenotypic variability observed in the mgΔloxPneo model for MFS. We characterize the model mgΔloxPneo, in two different mouse strains, the C57BL/6 and the 129/Sv strain. Mutant animals from both strains present defective microfibrillar deposition, emphysema, deterioration of aortic wall and kyphosis. However, the onset of a clinical phenotypes is earlier in the 129/Sv than in C57BL/6 background, indicating the existence of genetic modifiers of MFS between these two mouse strains. In addition, we characterized a wide clinical variability within the 129/Sv heterozygotes, suggesting involvement of epigenetic factors in disease severity. Finally, we show a strong negative correlation between overall levels of Fbn1 expression and the severity of the phenotypes. These results corroborated with studies, using animal models, as well with MFS patients, where the levels of normal fibrillin-1 seem to have the potential to modulate the clinical severity of the disease. In addition, the study also aims to evaluate new treatment possibilities for MFS in this same model. (AU) | |