African American ancestry contribution to asthma and atopic dermatitis

Abstract

Objective: Asthma and atopic dermatitis (AD) are complex diseases with striking disparities across racial and ethnic groups, which may be partly attributable to genetic factors. Here we summarize current knowledge from asthma and AD genome-wide association studies (GWAS) and pharmacogenetic studies in African ancestry populations.

Data sources: GWAS catalog; PUBMed.

Study selections: GWAS catalog studies with trait annotations "asthma" and "atopic eczema" and African ancestry individuals in the discovery dataset; the recent CAAPA asthma GWAS; reports on pharmacogenetic studies in asthma and AD.

Results: Although GWASs have revolutionized gene discovery for multiple complex traits, African Americans continue to be severely underrepresented in sufficiently powered genetics studies. Indeed, of the 16 asthma and 21 AD loci that reached genomewide significance in Europeans, very few have replicated in African ancestry populations. Challenges in comparing results from European vs African ancestry cohorts include modest sample size, differences in risk allele frequency, effect size, correlation between genetic variants, and environmental exposure in evolutionary history. African Americans also constitute a small percentage of dermatological and respiratory-focused clinical trials. Pharmacogenetic studies have similarly been focused largely on non-Hispanic whites, despite compelling evidence that genetic variation from different ancestral backgrounds may alter therapeutic efficacy of asthma and AD drugs.

Conclusion: Large-scale genetic studies of asthma and AD in African Americans are essential to reduce research and health disparities and empower scientific discoveries.