Table 1.

Genes and single nucleotide polymorphisms (SNPs) selected for the association analysis.

Gene and Its Chromosomal Localization	rs ID and Polymorphism (Amino Acid Substitution)	Encoded Protein	Known (Putative) Effects on Level/Activity of the Product	Bioactive Molecules Mediating Neurohumoral Signal Transduction Pathways
HTR1A 5q12.3	rs6295 −1019 G>C	Serotonin 1A receptor	SNP blocks the function of specific repressors Hes1, Hes5 and Deaf1, resulting in increased 5-HT1A autoreceptor expression in animal models and humans [12].	Serotonin
NOS3 (eNOS) 7q36.1	rs2070744 −786 T>C	Endothelial nitric oxide synthase	SNP affects the NOS3 transcription [13] and the plasma NO level [14].	Nitric oxide
ADRA1A 8p21.2	rs1048101 1039 A>G (Cys347Arg)	α 1A-adrenergic receptor	Amino acid substitution Cys347Arg affects receptor interactions with G-proteins and intracellular signal transduction [15].	Epinephrine, norepinephrine
ADRB1 10q25.3	rs1801253 1165 G>C (Gly389Arg)	β 1-adrenergic receptor	Amino acid substitution Gly389Arg affects receptor interactions with G-proteins and intracellular signal transduction [16].	Epinephrine, norepinephrine
COMT 22q11.21	rs4680 472 G>A (Val158Met)	Catechol-O- methyltransferase	Amino acid substitution Val158Met affects the activity of catechol-O-methyltransferase [17].	Epinephrine, norepinephrine, dopamine
ADORA2A 22q11.23	rs5751876 1083 C>T (Tyr361Tyr)	Adenosine A2A receptor	SNP is associated with a level of anxiety after caffeine consumption [18,19] and incidence of panic attacks [20].	Adenosine