Asthma, Rhinitis and Chronic Obstructive Pulmonary Disease (COPD) are common respiratory diseases worldwide, characterized by systemic and local chronic inflammation of the airways and increasing bronchial responsiveness, that contribute substantially to morbidity and mortality in adults living in the developed world. They are complex and heterogeneous diseases resulting from interaction between genetic and environmental factors. Several genes, each with a small effect, are likely involved in the development of these diseases and might contribute to the phenotype variability according to environmental exposure. Many candidate genes are reported in the literature data in association to one, two or all three diseases, even if results of these studies are not always consistent. This work is a part of the GEIRD (Gene Environment Interaction Respiratory Diseases) project, a population-based case-control study, aimed to elucidate the role of environment and genetic factors in the occurrence, persistence, severity and control of inflammatory airway diseases. In particular, the PhD thesis project here presented is focused on candidate gene association analysis in a large and accurately defined series of Italian subjects, in order to identify genes involved in the susceptibility to Asthma, Rhinitis and COPD and susceptibility genes that may be common to all the three diseases. A total of 1175 individuals, including subjects affected by asthma, rhinitis and COPD (cases) and unaffected by airways inflammatory diseases (controls), have been enrolled. A DNA bank, from all the subjects participating to the study, was created. Candidate genes for the study was chosen on the basis of the analysis of literature data, considering single genes studies, GWAS and meta-analyses. A group of 69 genes, involved in pathways related to the all three studied diseases, as inflammation, innate immunity and immunoregulation, oxidative stress and metabolism of xenobiotics, regulation of the protease-antiprotease equilibrium, and tissue remodelling, were selected. A panel of 384 Tag SNPs, representative of the candidate genes, was genotyped by a customized multiplexed GoldenGate Genotyping assay (Illumina). A single-locus and multi-locus association analysis was conducted to evaluate association with the following phenotypes: current asthma, past asthma, total asthma (current and past), current atopic asthma, allergic rhinitis, non allergic rhinitis, total rhinitis (allergic and non allergic), and subjects presenting with chronic respiratory symptoms. A significant association (p<0,01) was observed between IL-13 (5q31) and past asthma, both SPINK-5 (5q31-q32) and GSTP-1 (11q13) and non-atopic rhinitis, NOS-1 (12q24.2-24.31) and chronic respiratory symptoms. More interestingly, polymorphisms in IL1RL-2 gene (2q12) were found associated to multiple phenotypes (current asthma, current atopic asthma, chronic respiratory symptoms, non atopic rhinitis, and total rhinitis) suggesting a possible role for this gene in all the studied respiratory diseases. Therefore, we decide to deepen the study performing an haplotype association analysis for these genes. This additional study confirmed the single-locus associations found and the involvement of IL-13, SPINK-5, GSTP-1, NOS-1 and IL1RL-2 genes in the susceptibility to inflammatory respiratory diseases. The results of this study can be used in the future for the development of new molecular genetic tests for the early identification of subgroups of patients who need a specific therapy or having an individual susceptibility to specific environmental risk factors, by the determination of their genetic risk profile. In the post-genomic era, searching and identification of genes associated with complex diseases are still one of the main challenges for dissecting human complex diseases. A better understanding of pathogenic mechanisms and the identification of molecular markers of disease and genomic profiles, associated to particular diseases phenotypes and clinical outcomes, will be offering new targets for pharmacological therapy and will be opening the way to possible future applications in disease treatment and prevention, by a more accurate prognosis determination and a more specific or even individual therapies.
CANDIDATE GENE ASSOCIATION ANALYSIS IN RESPIRATORY DISEASES – THE GEIRD PROJECT
LO PRESTI, Anna Rita
2012
Abstract
Asthma, Rhinitis and Chronic Obstructive Pulmonary Disease (COPD) are common respiratory diseases worldwide, characterized by systemic and local chronic inflammation of the airways and increasing bronchial responsiveness, that contribute substantially to morbidity and mortality in adults living in the developed world. They are complex and heterogeneous diseases resulting from interaction between genetic and environmental factors. Several genes, each with a small effect, are likely involved in the development of these diseases and might contribute to the phenotype variability according to environmental exposure. Many candidate genes are reported in the literature data in association to one, two or all three diseases, even if results of these studies are not always consistent. This work is a part of the GEIRD (Gene Environment Interaction Respiratory Diseases) project, a population-based case-control study, aimed to elucidate the role of environment and genetic factors in the occurrence, persistence, severity and control of inflammatory airway diseases. In particular, the PhD thesis project here presented is focused on candidate gene association analysis in a large and accurately defined series of Italian subjects, in order to identify genes involved in the susceptibility to Asthma, Rhinitis and COPD and susceptibility genes that may be common to all the three diseases. A total of 1175 individuals, including subjects affected by asthma, rhinitis and COPD (cases) and unaffected by airways inflammatory diseases (controls), have been enrolled. A DNA bank, from all the subjects participating to the study, was created. Candidate genes for the study was chosen on the basis of the analysis of literature data, considering single genes studies, GWAS and meta-analyses. A group of 69 genes, involved in pathways related to the all three studied diseases, as inflammation, innate immunity and immunoregulation, oxidative stress and metabolism of xenobiotics, regulation of the protease-antiprotease equilibrium, and tissue remodelling, were selected. A panel of 384 Tag SNPs, representative of the candidate genes, was genotyped by a customized multiplexed GoldenGate Genotyping assay (Illumina). A single-locus and multi-locus association analysis was conducted to evaluate association with the following phenotypes: current asthma, past asthma, total asthma (current and past), current atopic asthma, allergic rhinitis, non allergic rhinitis, total rhinitis (allergic and non allergic), and subjects presenting with chronic respiratory symptoms. A significant association (p<0,01) was observed between IL-13 (5q31) and past asthma, both SPINK-5 (5q31-q32) and GSTP-1 (11q13) and non-atopic rhinitis, NOS-1 (12q24.2-24.31) and chronic respiratory symptoms. More interestingly, polymorphisms in IL1RL-2 gene (2q12) were found associated to multiple phenotypes (current asthma, current atopic asthma, chronic respiratory symptoms, non atopic rhinitis, and total rhinitis) suggesting a possible role for this gene in all the studied respiratory diseases. Therefore, we decide to deepen the study performing an haplotype association analysis for these genes. This additional study confirmed the single-locus associations found and the involvement of IL-13, SPINK-5, GSTP-1, NOS-1 and IL1RL-2 genes in the susceptibility to inflammatory respiratory diseases. The results of this study can be used in the future for the development of new molecular genetic tests for the early identification of subgroups of patients who need a specific therapy or having an individual susceptibility to specific environmental risk factors, by the determination of their genetic risk profile. In the post-genomic era, searching and identification of genes associated with complex diseases are still one of the main challenges for dissecting human complex diseases. A better understanding of pathogenic mechanisms and the identification of molecular markers of disease and genomic profiles, associated to particular diseases phenotypes and clinical outcomes, will be offering new targets for pharmacological therapy and will be opening the way to possible future applications in disease treatment and prevention, by a more accurate prognosis determination and a more specific or even individual therapies.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14242/114565
URN:NBN:IT:UNIVR-114565