Genetic biomarkers of life-threatening pheochromocytoma-induced cardiomyopathy.

The release of excessive amounts of catecholamine by pheochromocytoma-paragangliomas (PPGL) can lead to life-threatening catecholamine-induced cardiomyopathy (CIC). Single-nucleotide polymorphisms of the beta1 and alpha-2c adrenergic receptors alter myocyte receptor function and enhanced norepinephrine release. We tested the hypothesis that such genetic variations may impact the risk of developing CIC in the context of PPGL. Thirty-one patients with PPGL, including nine with a history of CIC, were analyzed for alpha-2-adrenergic receptors: ADRA2C, beta-1 and beta-2 adrenergic receptors: ADRB1 and ADRB2 genotyping. CIC was defined either by a history of heart failure or cardiogenic shock associated with dilated or Takotsubo cardiomyopathy. Subjects were genotyped for ADRA2C (rs61767072 for del322_325), ADRB1 (rs1801252 for Ser49Gly and rs1801253 for Arg389Gly) and ADRB2 (rs1042713 for Arg16Gly and rs1042714 for Gln27Glu). Single-locus analysis revealed that variant in ADRA2C (alpha 2CDel322-325) was more common among patients with CIC than among controls (allele frequency, 0.44 vs 0.05; P< 0.001). The lack of alpha 2CDel322-325 polymorphism has a negative predictive value of 95% for the onset of CIC. In a replication cohort including 26 patients with PPGL whom eight have developed a CIC, the association between Alpha 2CDel322-325 and CIC was confirmed (allele frequency, 0.33 vs 0.; P= 0.0001). In conclusion, Alpha 2CDel322-325 through the identification of patients at low risk of developing CIC can help physicians to better determine the most appropriate therapeutic approach, notably in patients at high risk of surgical complications.