Association Study Of ORMDL3 Snps And Expression And Childhood Asthma In Beijing

Asthma is a chronic disease of bronchus which has affected nearly 15.5 billion people global [1, 2]. Like other hypersensitivity diseases, asthma has certain transmissibility. Though the pattern of its heredity remains unclear, it is presumed that a great number of genes are associated with it [3~6]. Asthma is a complex disorder whit multiple factors affection, the environmental factors play an important role in the cause of the disease. It has been a new trend to find out the connection between diseases and genes as the"post-genome"era goes by. It is difficult to discover and identify asthma-associated genes due to its pathogenesis[7, 8]. Genome-Wide Association Study, based on Single Nucleotide Polymorphisms study, has provided us a new tool. Moffatt has performed the first GWAS about childhood asthma and found that the tag-SNPs of ORMDL3 in chromosome 17q21 was associated with childhood asthma, and those SNPs were also associated with expression levels of ORMDL3 [9]. These results showed that ORMDL3 is a novel asthma-associated gene.ORMDL3 has a higher expression level in adult pancreas and liver, meanwhile higher in fetal lung, liver, kidney and pancreas [10].We have established an association study base on case-control cohort in Beijing. Generally 428 samples were recruited from Beijing Children's Hospital and Capital Institute of Pediatrics. All of them had been checked according to the International Study of Asthma and Allergies in Childhood questionnaire. We built an asthma case-control genomic DNA cohort in Beijing with the genomic DNA extracted from peripheral blood leukocytes. ORMDL3 was amplified to genotype its selected SNPs (rs7216389,rs7216558). A novel SNP was found during the course and has been registered in Hapmap website (www.hapmap.org) with the number ss184955580. Chisq was used to test the association between tag-SNPs (rs7216389,rs7216558) and childhood asthma and we found they are not significantly associated. The result can be explained in the following three aspects: 1) the multiplicity caused by regional population differences; 2) the limit and bias of study samples; 3) a boarder association including more SNPs in ORMDL3 might lead to another conclusion.Since the associated SNPs have racial difference, the associated SNPs in ORMDL3 vary in different people cohorts. And the expression level of genes in different areas can be different under the circumstances, thus geography and environmental factors could affect some certain gene expression [11]. Reverse transcription polymerase chain reaction was used to build a smei-quantitaled test for the association between ORMDL3 expression level and childhood asthma. The expression levels of ORMDL3 are higher in asthmatic children than those in control. It pointed that high level of ORMDL3 expression is a risk factor for childhood asthma.Asthma is a complex disorder which is affected by immune response, genetic and environmental factors. Indoor air qualities allergens and life-style information were gathered in our study. Logistic was used to identify the association between genetic factors, environmental factors, other related factors and childhood asthma.Logistic was used to tell the association between variances (expression level of ORMDL3, ORMDL3 SNPs, Asthma Family History, Life-Style information, Indoor Air Qualities and variances), i.e. the genetic factors, environmental factors and immune response and childhood asthma. Meanwhile, stepwise was participated to found the formula about risk factors and childhood asthma.Except for the association study about ORMDL3 expression levels and ORMDL3 SNPs, its protein structure and function is drawing more and more attention. Full-length ORMDL3 was amplified in our study, and inserted in a prokaryotic expression plasmid pET17b and eukaryotic expression plasmid pcDNA3.1(+). ORMDL3 was expressed in a prokaryotic system (E.coli BL21(DE3)) and a eukaryotic system (HEK293T cell line), in which its function was initially analyzed.Generally, 1) we built a asthma case-control cohort of genome DNA samples; 2) ORMDL3 SNPs (rs7216389,rs7216558) were genotyped and analyzed the association with childhood asthma; A novel SNP ss184955580 was found in ORMDL3 in our study; 3) a smei-quantitaled test about ORMDL3 expression levels was performed to analyze its difference between asthmatic children and control, and the association between with childhood asthma; 4) ORMDL3 SNPs, ORMDL3 expression levels, life-style information gathered form ISSAC questionnaire, indoor air qualities, IL-4, total IgE and special IgEs was analyzed and a formula about risk factors and childhood asthma was found; 5) ORMDL3 was cloned and expressed in a prokaryotic system (E.coli BL21(DE3)) and a eukaryotic system (HEK293T), in which its function was initial analyzed.