Moderate-to-severe asthma in individuals of European ancestry: a genome-wide association study

Nick Shrine, Michael A Portelli, Catherine John, María Soler Artigas, Neil Bennett, Robert Hall, Jon Lewis, Amanda P Henry, Charlotte K Billington, Azaz Ahmad, Richard J Packer, Dominick Shaw, Zara E K Pogson, Andrew Fogarty, Tricia M McKeever, Amisha Singapuri, Liam G Heaney, Adel H Mansur, Rekha Chaudhuri, Neil C ThomsonJohn W Holloway, Gabrielle A Lockett, Peter H Howarth, Ratko Djukanovic, Jenny Hankinson, Robert Niven, Angela Simpson, Kian Fan Chung, Peter J Sterk, John D Blakey, Ian M Adcock, Sile Hu, Yike Guo, Maen Obeidat, Don D Sin, Maarten van den Berge, David C Nickle, Yohan Bossé, Martin D Tobin, Ian P Hall, Christopher E Brightling, Louise V Wain, Ian Sayers

Research output: Contribution to journalArticlepeer-review

100 Citations (Scopus)

Abstract

BACKGROUND: Few genetic studies that focus on moderate-to-severe asthma exist. We aimed to identity novel genetic variants associated with moderate-to-severe asthma, see whether previously identified genetic variants for all types of asthma contribute to moderate-to-severe asthma, and provide novel mechanistic insights using expression analyses in patients with asthma.

METHODS: In this genome-wide association study, we used a two-stage case-control design. In stage 1, we genotyped patient-level data from two UK cohorts (the Genetics of Asthma Severity and Phenotypes [GASP] initiative and the Unbiased BIOmarkers in PREDiction of respiratory disease outcomes [U-BIOPRED] project) and used data from the UK Biobank to collect patient-level genomic data for cases and controls of European ancestry in a 1:5 ratio. Cases were defined as having moderate-to-severe asthma if they were taking appropriate medication or had been diagnosed by a doctor. Controls were defined as not having asthma, rhinitis, eczema, allergy, emphysema, or chronic bronchitis as diagnosed by a doctor. For stage 2, an independent cohort of cases and controls (1:5) was selected from the UK Biobank only, with no overlap with stage 1 samples. In stage 1 we undertook a genome-wide association study of moderate-to-severe asthma, and in stage 2 we followed up independent variants that reached the significance threshold of p less than 1 × 10-6 in stage 1. We set genome-wide significance at p less than 5 × 10-8. For novel signals, we investigated their effect on all types of asthma (mild, moderate, and severe). For all signals meeting genome-wide significance, we investigated their effect on gene expression in patients with asthma and controls.

FINDINGS: We included 5135 cases and 25 675 controls for stage 1, and 5414 cases and 21 471 controls for stage 2. We identified 24 genome-wide significant signals of association with moderate-to-severe asthma, including several signals in innate or adaptive immune-response genes. Three novel signals were identified: rs10905284 in GATA3 (coded allele A, odds ratio [OR] 0·90, 95% CI 0·88-0·93; p=1·76 × 10-10), rs11603634 in the MUC5AC region (coded allele G, OR 1·09, 1·06-1·12; p=2·32 × 10-8), and rs560026225 near KIAA1109 (coded allele GATT, OR 1·12, 1·08-1·16; p=3·06 × 10-9). The MUC5AC signal was not associated with asthma when analyses included mild asthma. The rs11603634 G allele was associated with increased expression of MUC5AC mRNA in bronchial epithelial brush samples via proxy SNP rs11602802; (p=2·50 × 10-5) and MUC5AC mRNA was increased in bronchial epithelial samples from patients with severe asthma (in two independent analyses, p=0·039 and p=0·022).

INTERPRETATION: We found substantial shared genetic architecture between mild and moderate-to-severe asthma. We also report for the first time genetic variants associated with the risk of developing moderate-to-severe asthma that regulate mucin production. Finally, we identify candidate causal genes in these loci and provide increased insight into this difficult to treat population.

FUNDING: Asthma UK, AirPROM, U-BIOPRED, UK Medical Research Council, and Rosetrees Trust.

Original languageEnglish
Pages (from-to)20-34
Number of pages15
JournalLancet Respiratory Medicine
Volume7
Issue number1
DOIs
Publication statusPublished - Jan 2019
Externally publishedYes

Fingerprint

Dive into the research topics of 'Moderate-to-severe asthma in individuals of European ancestry: a genome-wide association study'. Together they form a unique fingerprint.

Cite this