Background Hay fever or seasonal allergic rhinitis (AR) is a chronic disorder associated with IgE sensitization to grass. The underlying genetic variants have not been studied comprehensively. There ...is overwhelming evidence that those who have older siblings have less AR, although the mechanism for this remains unclear. Objective We sought to identify common genetic variant associations with prevalent AR and grass sensitization using existing genome-wide association study (GWAS) data and to determine whether genetic variants modify the protective effect of older siblings. Method Approximately 2.2 million genotyped or imputed single nucleotide polymorphisms were investigated in 4 large European adult cohorts for AR (3,933 self-reported cases vs 8,965 control subjects) and grass sensitization (2,315 cases vs 10,032 control subjects). Results Three loci reached genome-wide significance for either phenotype. The HLA variant rs7775228, which cis -regulates HLA-DRB4 , was strongly associated with grass sensitization and weakly with AR ( Pgrass = 1.6 × 10−9 ; PAR = 8.0 × 10−3 ). Variants in a locus near chromosome 11 open reading frame 30 (C11orf30) and leucine-rich repeat containing 32 (LRRC32) , which was previously associated with atopic dermatitis and eczema, were also strongly associated with both phenotypes (rs2155219; Pgrass = 9.4 × 10−9 ; PAR = 3.8 × 10−8 ). The third genome-wide significant variant was rs17513503 (Pgrass = 1.2 × 10−8 ; PAR = 7.4 × 10−7 ) which was located near transmembrane protein 232 (TMEM232) and solute carrier family 25, member 46 ( SLC25A46 ). Twelve further loci with suggestive associations were also identified. Using a candidate gene approach, where we considered variants within 164 genes previously thought to be important, we found variants in 3 further genes that may be of interest: thymic stromal lymphopoietin ( TSLP ), Toll-like receptor 6 ( TLR6 ) and nucleotide-binding oligomerization domain containing 1 ( NOD1/CARD4 ). We found no evidence for variants that modified the effect of birth order on either phenotype. Conclusions This relatively large meta-analysis of GWASs identified few loci associated with AR and grass sensitization. No birth order interaction was identified in the current analyses.
Low concentrations of the anti-inflammatory protein CC16 (approved symbol SCGB1A1) in serum have been associated with accelerated decline in forced expiratory volume in 1 s (FEV1) in patients with ...chronic obstructive pulmonary disease (COPD). We investigated whether low circulating CC16 concentrations precede lung function deficits and incidence of COPD in the general population.
We assessed longitudinal data on CC16 concentrations in serum and associations with decline in FEV1 and incidence of airflow limitation for adults who were free from COPD at baseline in the population-based Tucson Epidemiological Study of Airway Obstructive Disease (TESAOD n=960, mean follow-up 14 years), European Community Respiratory Health Survey (ECRHS-Sp n=514, 11 years), and Swiss Cohort Study on Air Pollution and Lung Diseases in Adults (SAPALDIA n=167, 8 years) studies. Additionally, we measured circulating CC16 concentrations in samples from children aged 4-6 years in the Tucson Children's Respiratory Study (n=427), UK Manchester Asthma and Allergy Study (n=481), and the Swedish Barn/children, Allergy, Milieu, Stockholm, Epidemiological survey (n=231) birth cohorts to assess whether low CC16 concentrations in childhood were predictive for subsequent lung function.
After adjustment for sex, age, height, smoking status and intensity, pack-years, asthma, and FEV1 at baseline, we found an inverse association between CC16 concentration and decline in FEV1 in adults in TESAOD (4·4 mL/year additional FEV1 decline for each SD decrease in baseline CC16 concentration, p=0·0014) and ECRHS-Sp (2·4 mL/year, p=0·023); the effect in SAPALDIA was marginal (4·5 mL/year, p=0·052). Low CC16 concentration at baseline was also associated with increased risk of incident stage 2 airflow limitation (ratio of FEV1 to forced expiratory volume FEV1/FVC less than 70% plus FEV1 % predicted less than 80%) in TESAOD and ECRHS-Sp. In children, the lowest tertile of CC16 concentrations was associated with a subsequent FEV1 deficit of 68 mL up to age 16 years (p=0·0001), which was confirmed in children who had never smoked by age 16 years (-71 mL, p<0·0001).
Low concentrations of CC16 in serum are associated with reduced lung function in childhood, accelerated lung function decline in adulthood, and development of moderate airflow limitation in the general adult population.
National Heart, Lung, and Blood Institute and European Union Seventh Framework Programme.
Background Genome-wide association studies have identified determinants of chronic obstructive pulmonary disease, asthma, and lung function level; however, none have addressed decline in lung ...function. Objective We conducted the first genome-wide association study on the age-related decrease in FEV1 and its ratio to forced vital capacity (FVC) stratified a priori by asthma status. Methods Discovery cohorts included adults of European ancestry (1,441 asthmatic and 2,677 nonasthmatic participants: the Epidemiological Study on the Genetics and Environment of Asthma, the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults, and the European Community Respiratory Health Survey). The associations of FEV1 and FEV1 /FVC ratio decrease with 2.5 million single nucleotide polymorphisms (SNPs) were estimated. Thirty loci were followed up by in silico replication (1,160 asthmatic and 10,858 nonasthmatic participants: Atherosclerosis Risk in Communities, the Framingham Heart Study, the British 1958 Birth Cohort, and the Dutch Asthma Study). Results Main signals identified differed between asthmatic and nonasthmatic participants. None of the SNPs reached genome-wide significance. The association between the height-related gene DLEU7 and FEV1 decrease suggested for nonasthmatic participants in the discovery phase was replicated (discovery, P = 4.8 × 10−6 ; replication, P = .03), and additional sensitivity analyses point to a relation to growth. The top ranking signal, TUSC3 , which is associated with FEV1 /FVC ratio decrease in asthmatic participants ( P = 5.3 × 10−8 ), did not replicate. SNPs previously associated with cross-sectional lung function were not prominently associated with decline. Conclusions Genetic heterogeneity of lung function might be extensive. Our results suggest that genetic determinants of longitudinal and cross-sectional lung function differ and vary by asthma status.
Background Asthma is a heterogeneous disease in which age of onset plays an important role. Objective We sought to identify the genetic variants associated with time to asthma onset (TAO). Methods We ...conducted a large-scale meta-analysis of 9 genome-wide association studies of TAO (total of 5462 asthmatic patients with a broad range of age of asthma onset and 8424 control subjects of European ancestry) performed by using survival analysis techniques. Results We detected 5 regions associated with TAO at the genome-wide significant level ( P < 5 × 10−8 ). We evidenced a new locus in the 16q12 region (near cylindromatosis turban tumor syndrome gene CYLD ) and confirmed 4 asthma risk regions: 2q12 (IL-1 receptor–like 1 IL1RL1 ), 6p21 (HLA-DQA1) , 9p24 (IL33) , and 17q12-q21 (zona pellucida binding protein 2 ZPBP2 –gasdermin A GSDMA ). Conditional analyses identified 2 distinct signals at 9p24 (both upstream of IL33 ) and 17q12-q21 (near ZPBP2 and within GSDMA ). Together, these 7 distinct loci explained 6.0% of the variance in TAO. In addition, we showed that genetic variants at 9p24 and 17q12-q21 were strongly associated with an earlier onset of childhood asthma ( P ≤ .002), whereas the 16q12 single nucleotide polymorphism was associated with later asthma onset ( P = .04). A high burden of disease risk alleles at these loci was associated with earlier age of asthma onset (4 vs 9-12 years, P = 10−4 ). Conclusion The new susceptibility region for TAO at 16q12 harbors variants that correlate with the expression of CYLD and nucleotide-binding oligomerization domain 2 (NOD2) , 2 strong candidates for asthma. This study demonstrates that incorporating the variability of age of asthma onset in asthma modeling is a helpful approach in the search for disease susceptibility genes.
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