Joint test of allelic dosage and local ancestry identifies INTS3 as new susceptibility gene for asthma among african american individuals.

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Conference Proceeding

Publication Date


Publication Title

Am J Respir Crit Care Med.


Introduction/Rational: African American individuals have a higher prevalence rate and complication rate for asthma when compared with European Americans. We sought to identify genetic variants related to asthma status utilizing methods which leverage information on both genetic association and genetic ancestry. Methods: The Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE) is a longitudinal asthma cohort study from a large health system serving southeast Michigan. The analytic sample consisted of asthma case and control individuals who self-identified as African American and who had genome-wide SNP array data (Affymetrix Axiom AFR GeneChip). Two approaches were used to identify risk alleles: 1) a standard GWAS association analysis using logistic regression and the software package GENESIS to assess the relationship between each single nucleotide polymorphism (SNP) and asthma status, and 2) a joint association test using the software package MIXSCORE to estimate the combined effect of SNP dosage and local ancestry state on asthma status. Genetic ancestry at each marker (i.e., local ancestry) was determined using the program RFMix. All the association models included covariates to adjust for age, sex, BMI, smoking status, and global ancestry. Results: Data were available for 1891 African American study participants (1325 asthma cases and 566 controls). Using the standard genome-wide association approach, we did not identify a single allele that met the conservative, Bonferronicorrected threshold (5x10 -8 ) for statistical significance. However, using the joint association approach, we identified a SNP, rs114682783, that did reach genome-wide statistical significance (P=4.23x10 -8 ). This SNP is located in an intron of the INTS3 gene in the chromosomal region 1q21.3; its minor allele frequency was 4.4% in our African American sample, but much rarer (



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