Lack of genetic susceptibility in takotsubo cardiomyopathy: a case-control study.

BACKGROUND: Takotsubo cardiomyopathy (TCM), also known as "broken heart syndrome", is a type of heart failure characterized by transient ventricular dysfunction in the absence of obstructive coronary lesions. Although associated with increased levels of catecholamines, pathophysiological mechanisms are unknown. Relapses and family heritability indicate a genetic predisposition. Several small studies have investigated associations between three different loci; the ß1-adrenic receptor (ADRB1), G-protein-coupled receptor kinase 5 (GRK5), Bcl-associated athanogene 3 (BAG3) and TCM but no consensus has been reached. METHODS: Participants were recruited using the Swedish Coronary Angiography and Angioplasty Register (SCAAR). TCM patients without coronary artery disease (CAD)(n = 258) were identified and age- and sex-matched subjects with (n = 164) and without (n = 243) CAD were selected as controls. DNA was isolated from saliva and genotyped for candidate single nucleotide polymorphisms in the ADRB1, GRK5 and BAG3 genes. Allele frequencies and Odds Ratios (OR) with 95% Confidence Intervals (CI) for the investigated polymorphisms were compared, respectively calculated for TCM patients and controls. RESULTS: There were no differences in allele frequencies between TCM patients and controls. OR (CI) for TCM patients having at least one minor allele using controls as reference were 1.07 (0.75-1.55) for ADRB1, 0.45 (0.11-1.85) for GRK5 and 1.27 (0.74-2.19) for BAG3. CONCLUSION: By genotyping a large takotsubo cohort, we demonstrate a lack of association between candidate SNPs in the ADRB1, GRK5 and BAG3 genes, earlier suggested to contribute to TCM. Our result indicates a need to expand the search for new genetic candidates contributing to TCM.