Vasovagal syncope patients and the C825T GNB3 polymorphism.

Objective: The G protein is responsible for signal intracellular transduction and participates in cardiovascular reflexes. C825T polymorphism of the gene encodes the B3 subunit of G protein (GNB3) and causes the increased intracellular signal transduction. The aim was the evaluation GNB3 C825T polymorphism manifestation in vasovagal patients with no other diseases.
Methods: In 68 positive tilted patients genomic DNA was extracted from blood using an extraction kit. The GNB3 C825T polymorphism was diagnosed by restriction of the PCR amplicon with BseDI (MBI Fermentas). All patients were genotyped and next analyzed in regard to typical vasovagal history.
Results: The prevalence of genotype CC was 38%. Genotypes CT and TT were found equally in 31% of cases. The C allele in comparison to the T allele appeared in 54% vs 46% (p>0.05). Typical vasovagal history was present in 83% of patients. The frequency of GNB3 825T allele was significantly higher in patients with non-typical vasovagal history than in group with typical history (p<0.001).
Conclusions: Genotype CC GNB3 is the most popular in vasovagal patients. The predisposition to vasovagal syncope seems to be not associated with the GNB3 825T allele. Further studies are planned to clarify the genotype/phenotype relationship in vasovagal patients.