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Study Description

Asthma is a complex disease where the interplay between genetic factors and environmental exposures influences susceptibility and disease prognosis. Asthmatics of African descent tend to have more severe asthma and more severe clinical symptoms than individuals of European ancestry. Advances in genetic and genomic technologies have revolutionized gene discovery for several complex diseases, but going to the next step in gene discovery for asthma among populations of African descent requires considering unique characteristics of this ethnic group, including adequate sample sizes and population stratification due to (European and African) admixture. Thus far, coverage of common genetic markers both in public databases and commercially available SNP chips has been inadequate to detect and measure genetic associations among African admixed populations. The aim of this study was therefore to catalog genetic diversity in populations of African descent, especially those whose ancestry reflects the African Diaspora in the Americas.

  • Study Type: Population Genomics
  • dbGaP estimated ancestry components using GRAF-pop
  • Number of study subjects that have individual level data available through Authorized Access: 917

Authorized Access
Publicly Available Data (Public ftp)

Connect to the public download site. The site contains release notes and manifests. If available, the site also contains data dictionaries, variable summaries, documents, and truncated analyses.

Study Inclusion/Exclusion Criteria

DNA samples of 1004 individuals of African ancestry were whole genome sequenced. These individuals were selected across North and South America, the Caribbean, and continental Africa, in order to represent a large spectrum of African ancestry. 87 samples from 2 populations were excluded due to regulatory constraints, leaving 917 samples for analysis.

Molecular Data
TypeSourcePlatformNumber of Oligos/SNPsSNP Batch IdComment
Whole Genome Genotyping Illumina HumanOmni2.5-8v1_A N/A 1059487
Whole Genome Sequencing Illumina HiSeq 2000 N/A N/A Variant Call Format
Study History

In September, 2011, the Consortium on Asthma among African-ancestry Populations in the Americas (CAAPA) received support from the National Institutes of Health, National Heart, Lung and Blood Institute, to achieve two broad goals: Discovery of genes conferring risk to asthma among individuals of African ancestry catalog genetic diversity in populations of African descent, especially those whose ancestry reflects the African Diaspora in the Americas. To achieve these goals, CAAPA investigators have generated whole genome sequence data on ~1,000 asthmatics and non-asthmatics, all of African ancestry, selected across North and South America, the Caribbean, and continental Africa, to represent a large spectrum of African ancestry.

Selected publications
Diseases/Traits Related to Study (MESH terms)
Links to Related Resources
Authorized Data Access Requests
Study Attribution