RESUMO
BACKGROUND: Asthma is a complex disease that has genetic and environmental causes. The genetic factors associated with susceptibility to asthma remain largely unknown. METHODS: We carried out a genomewide association study involving children with asthma. The sample included 793 North American children of European ancestry with persistent asthma who required daily inhaled glucocorticoid therapy and 1988 matched controls (the discovery set). We also tested for genomewide association in an independent cohort of 917 persons of European ancestry who had asthma and 1546 matched controls (the replication set). Finally, we tested for an association between 20 single-nucleotide polymorphisms (SNPs) at chromosome 1q31 and asthma in 1667 North American children of African ancestry who had asthma and 2045 ancestrally matched controls. RESULTS: In our meta-analysis of all samples from persons of European ancestry, we observed an association, with genomewide significance, between asthma and SNPs at the previously reported locus on 17q21 and an additional eight SNPs at a novel locus on 1q31. The SNP most strongly associated with asthma was rs2786098 (P=8.55x10(-9)). We observed replication of the association of asthma with SNP rs2786098 in the independent series of persons of European ancestry (combined P=9.3x10(-11)). The alternative allele of each of the eight SNPs on chromosome 1q31 was strongly associated with asthma in the children of African ancestry (P=1.6x10(-13) for the comparison across all samples). The 1q31 locus contains the 1q31 locus contains DENND1B, a gene expressed by natural killer cells and dendritic cells. DENND1B protein is predicted to interact with the tumor necrosis factor α receptor [corrected]. CONCLUSIONS: We have identified a locus containing DENND1B on chromosome 1q31.3 that is associated with susceptibility to asthma.
Assuntos
Asma/genética , Cromossomos Humanos Par 1 , Proteínas Adaptadoras de Sinalização de Receptores de Domínio de Morte/genética , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Fatores de Troca do Nucleotídeo Guanina/genética , Polimorfismo de Nucleotídeo Único , População Branca/genética , População Negra/genética , Estudos de Casos e Controles , Criança , Cromossomos Humanos Par 17 , Feminino , Humanos , Masculino , Metanálise como Assunto , América do Norte , Razão de Chances , Receptores do Fator de Necrose Tumoral/metabolismoAssuntos
Asma/epidemiologia , Asma/genética , Cromossomos Humanos Par 17/genética , Proteínas de Membrana/genética , Nicotiana/efeitos adversos , Fumar/efeitos adversos , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Estudos de Coortes , Feminino , Predisposição Genética para Doença , Humanos , Lactente , Recém-Nascido , Masculino , Polimorfismo de Nucleotídeo Único , Fatores de Risco , População Branca/genéticaRESUMO
Inflammatory bowel disease (IBD) is a common inflammatory disorder with complex etiology that involves both genetic and environmental triggers, including but not limited to defects in bacterial clearance, defective mucosal barrier and persistent dysregulation of the immune response to commensal intestinal bacteria. IBD is characterized by two distinct phenotypes: Crohn's disease (CD) and ulcerative colitis (UC). Previously reported GWA studies have identified genetic variation accounting for a small portion of the overall genetic susceptibility to CD and an even smaller contribution to UC pathogenesis. We hypothesized that stratification of IBD by age of onset might identify additional genes associated with IBD. To that end, we carried out a GWA analysis in a cohort of 1,011 individuals with pediatric-onset IBD and 4,250 matched controls. We identified and replicated significantly associated, previously unreported loci on chromosomes 20q13 (rs2315008[T] and rs4809330[A]; P = 6.30 x 10(-8) and 6.95 x 10(-8), respectively; odds ratio (OR) = 0.74 for both) and 21q22 (rs2836878[A]; P = 6.01 x 10(-8); OR = 0.73), located close to the TNFRSF6B and PSMG1 genes, respectively.