Study of Kir6.2/KCNJ11 gene in a sudden cardiac death pedigree.

In clinic, the patients with acute myocardial infarction (AMI) are at high risk to develop ischemia-induced ventricular arrhythmias leading to sudden cardiac death (SCD). Some studies suggest that individual susceptibility to ischemia-induced arrhythmia may be related to the genes encoding ion channels. One of them is the cardiac ATP-sensitive potassium channel (K(ATP)), which is an octamer composed of four pore-forming inwardly rectifying potassium-channel subunits (Kir6.2) and four regulatory sulfonylurea-receptor subunits (SUR2A). They play important roles in the physiology and pathophysiology of cardiovascular system by coupling the metabolic state of the cells to cellular electrical activity. So far, some mutations and polymorphisms of Kir6.2/KCNJ11 gene showed significant correlation with type 2 diabetes. But it was not sure whether it was associated with acute myocardial diseases. Hence a complete mutational analysis of Kir6.2/KCNJ11 gene was performed in a pedigree of sudden cardiac death. The complete coding region and the intron-exon boundaries of KCNJ11 were amplified from genomic DNA using polymerase chain reaction (PCR). Direct sequencing was done to identify any mutations and then further confirmed by restriction site polymorphism (RSP) approach. No mutation was detected in the samples analyzed, a common polymorphism K23E (A>G) was noticed in this pedigree and the proband showed a homozygote genotype (G/G). The result suggests that the Kir6.2/KCNJ11 gene is not related to sudden cardiac death in this family.