Europace Advance Access originally published online on April 26, 2007
Europace 2007 9(8):585-588; doi:10.1093/europace/eum059
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BASIC SCIENCE
The Arg389Gly ß1-adrenergic receptor gene polymorphism and susceptibility to faint during head-up tilt test


1 Department of Electrocardiology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico; 2 Department of Physiology, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano 1, Col. Sección XVI, Tlalpan 14080, México, D.F., Mexico; 3 Cardiovascular Diseases Genomic and Proteomic Study Group, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
Aims To investigate the association of the Gly389 allele with positive head-up tilt test (HUT) in a Mexican Mestizo population.
Methods and results HUT results were compared between carriers (one or two copies of the Gly389 allele) and non-carriers (Arg389Arg genotype) of the Gly389 allele of the ß1AR gene in 50 patients with unexplained syncope. Thirty-three patients (66%) had a positive HUT. Patients with a positive HUT had a higher Gly389 allele frequency compared with those with a negative test (30.3 vs. 3%; OR 13; pC = 0.012). Moreover, when comparing positive HUT in passive drug-free phase, positive HUT in pharmacological (nitrate) phase, and negative (both phases), a decreasing gradient in the frequencies of the Gly389 allele was found among the three groups: 45.4, 22.7, and 3%, respectively.
Conclusion An association of positive tilt table testing to a single nucleotide polymorphism with a Gly to Arg switch at position 389 of the ß1AR was found. This polymorphism may contribute to susceptibility to faint during orthostatic challenge.
Key Words: Autonomic nervous system, Adrenergic receptors, Vasovagal syncope, Genetics
* Corresponding author. Tel: 5255 5573 2911/ext. 1278; fax: 5255 5573 0926. E-mail address: gvargas63{at}yahoo.com
The two authors contributed equally and the order of authorship is arbitrary.
Manuscript submitted 9 August 2006. Accepted after revision 8 March 2007.