A Genome-Wide Association Study (GWAS) of Takotsubo syndrome

Abstract Background Takotsubo syndrome (TS) is an acute cardiac condition of unknown etiology characterized by transient regional systolic dysfunction of the left and/or right ventricle. Several studies have suggested the importance of genetics; however, studies are limited and have presented conflicting results. Purpose To identify potential genetic risk variants associated with TS. Methods A case-control GWAS in three steps; I) A discovery study with Swedish takotsubo cases (n=260) and age- and sex-matched controls without heart disease from the UK Biobank (n=3034), II) A replication study of Swedish takotsubo cases (n=250) and sex- and age-matched Swedish controls without myocardial infarction from the Swedish coronary angiography and angioplasty register (n=229), III) A Meta-analysis of study I-II with extended controls from the UK-biobank (n=5161). Genotyping was performed using the Axiom® UK Biobank Genotyping Array including 820 000 single nucleotide polymorphisms (SNPs). After applying filters and QC control around 480 000 SNPs remained with a Bonferroni corrected p-value 1*10^-7, minor allele frequency (MAF 1.5-2%), Hardy-Weinberg (HWE) 10^-6. QC, filtering and analysis were performed in PLINK 1.9 and R v 4.0. Results In the discovery (I) 1490 SNP:s fulfilled a significance level of <10^-4, of which 36 SNP:s replicated (II) with a significance level of <10^-2, 11 reached a significance level of 10^-7 in the meta-analysis (III). One of the 36 SNP:s, rs1614887, replicated (II) with a significance level of 10^-3. This SNP is an intron variant in the butyrophilin subfamily 2 member A2 gene, a glycoprotein receptor involved in lipid, fatty-acid and sterol metabolism highly expressed in the heart. Of the 11 SNP:s with a significance level of 10^-7 in the meta-analysis (III) several risk variants were associated with psoriasis. Conclusions This is the largest GWAS of takotsubo syndrome performed so far, identifying one candidate gene and several potential risk variants. Further research of genetic risk variants in TS is warranted.