A screen of candidate genes and influence of β2-adrenergic receptor genotypes in postural tachycardia syndrome

Kim K. Nickander, Paula J. Carlson, Raul A. Urrutia, Michael Camilleri, Phillip A. Low

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Objective: To screen candidate genes, encoding β2- adrenergic receptor (β2AR), α2C-adrenergic receptor (α2CAR), norepinephrine transporter (NET), and mitochondrial complex I (COI), for common single nucleotide polymorphisms (SNPs) in patients with postural tachycardia syndrome (POTS); alterations could potentially cause or aggravate orthostatic tachycardia and to relate β2AR SNPs, known to effect venomotor tone, to heart rate (HR) and blood pressure measurements during 10-min head-up tilt. Methods: (a) DNA extraction from leukocytes of 29 patients with POTS; (b) Denaturing high performance liquid chromatography analysis to screen for the 12-bp deletion (Del322-325) in α2CAR and for the alanine to proline mutation at amino acid 457 (Ala457Pro) in NET; (c) Systematic direct sequence analysis to screen for SNPs in β2AR, NET, and COI. Results: Three common polymorphisms were abundant in at least one allele in β2AR resulting in a cysteine to arginine in the 5′ promoter region (72% of patients), an arginine to glycine at amino acid-16 (Gly16; 86%), and a glutamine to glutamic acid at amino acid-27 (Glu27; 66%), a frequency that was no different to the normal Caucasian population. Orthostatic HR was significantly greater in patients with Glu27. Diastolic blood pressure (DBP) was significantly lower in a subset of patients with Gly16 whose HR were ≥120 beats/min with head-up tilt. All patients did not show the Ala457Pro mutation of NET; all sequence variants detected in α2CAR, NET, and COI were not considered causally related to POTS. Conclusions: Of the candidate genes screened, none harbored a SNP considered to be causally related to POTS. There was significant association of HR and DBP with SNPs of the gene encoding β2AR; Gly16 or Glu27 could aggravate orthostatic tachycardia by excessive venous pooling.

Original languageEnglish (US)
Pages (from-to)97-103
Number of pages7
JournalAutonomic Neuroscience: Basic and Clinical
Volume120
Issue number1-2
DOIs
StatePublished - Jun 15 2005

Keywords

  • Complex I
  • Norepinephrine transporter
  • POTS
  • SNP
  • Single nucleotide polymorphism
  • α-adrenergic receptor
  • β-adrenergic receptor

ASJC Scopus subject areas

  • Endocrine and Autonomic Systems
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

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