Beta 3 subunit of G-protein and its influence on autonomic nervous system in patients with vasovagal syncope

Abstract

OBJECTIVES: The aim of this prospective study was to investigate the impact of genetic polymorphisms of β3 subunit of G-protein on the occurrence of vasovagal syncope, hemodynamic parameters and heart rate variability during head-up tilt test (HUT). BACKGROUND: G-proteins play an important role in the intracellular transmission of impulses in cardiovascular autonomic refl exes. METHODS: In 157 patients with suspected vasovagal syncope HUT was performed. Ninety-one patients (38 men, 53 women, mean age 48 ± 17 years) had positive HUT. Control group consisted of 109 subjects (69 men, 40 women, mean age 37 ± 16 years) with no history of syncope. Results of HUT, hemodynamic parameters and LF, HF, LF/HF, SDNN, RMSSD parameters of heart rate variability were compared in patients with different genotypes. C825T polymorphism of β3 subunit of G-protein was determined in the study subjects.

Towards Understanding the Genetic Nature of Vasovagal Syncope

“…A comparison of VVS patients with healthy controls revealed that none of these genes are associated with VVS [31,46,47]. Other researchers obtained similar results for the GNAS1 [28], GNB3 [26], and RGS2 genes [32]; the sample size of the group analyzed in [32] was rather large (300 children with VVS and 150 healthy children). Furthermore, no association of the SNPs rs17363334, rs77354509, or rs79516120 of the GNB1 gene encoding G protein subunit beta 1 and c.87 + 34G > A of the GNG2 gene encoding G protein subunit gamma 2 with VVS was detected [45].…”

“…However, in actual practice, the study groups (and especially the control one) were often formed using questionnaire data only. The study group could include individuals with suspected VVS rather than those with a definitive diagnosis [ 26 ], or include patients with a history of both typical and atypical VVS [ 27 ]. In individual studies, patients and controls in the groups being compared were members of the same families, which does not meet the sample independence criterion [ 28 ].…”

Genetic Analysis of Cardiac Syncope-Related Genes in Korean Patients with Recurrent Neurally Mediated Syncope

“…Based on such a strong family history of syncope, some authors suggested a genetic involvement in the pathophysiological cascade leading to syncope [ 7 , 9 ]. In Western studies, an association between the cause of NMS and various single-nucleotide polymorphisms (SNPs) in sympathetic activity-related genes was suggested [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]; however, the genetic factors associated with NMS have not been elucidated and the results thus far have been conflicting [ 7 , 19 , 20 ]. There are many difficulties in explaining the cause of NMS based only on SNPs.…”