Study to establish genetic association of cardiac conduction defect in Indian patients undergoing pacemaker implantation

Abstract

Background: The aim was to study the genetic association of cardiac conduction defects (CCDs) by evaluating single nucleotide polymorphism (SNP) in genes of SCN1B and KCNJ2 and to evaluate baseline characteristics between cases and controls.Methods: Case group consisted of 81 individuals with diagnosis of conduction disturbances who underwent permanent pacemaker implantation. The control group consisted of 79 unrelated individuals above 18 years of age of the local population not having a present or past personal or family history (first degree relatives) of any cardiac ailment especially CCDs. Isolation of genomic deoxyribonucleic acid (DNA) from all samples was done, genomic DNA was checked to ensure the presence of intact DNA.Results: SCN1B: SNP rs55742440 had no bearing on the protein except in producing a splice variant. SNP rs67701503 does not lie in the splice-site region, thus not having any significance in the regulation of the gene as well. NetGene2 analysis of SNP rs67486287 negates its presence in the splice site. KCNJ2:SNP rs199473653 leads to a missense amino acid change, resulting in homozygous GG variant found in almost equal frequency in both groups. SNP rs199473653 gene has not been reported as a disease causing mutation.Conclusions: The alteration of nucleotide in SCN1B intron (SNP rs55742440, rs67701503, rs67486287) between cases and controls was found to have no odds of affecting the outcome of CCD. There was no variation or alteration in nucleotide bases of KCNJ2 (SNP rs786205813, rs199473653) between the groups.