Expression of genes KCNQ1 and HERG encoding potassium ion channels Ikr, Iks in long QT syndrome.

Background: The KCNQ1 and HERG genes mutations are responsible for specific types of congenital long QT syndrome (LQT).
Aim: To examine the expression of KCNQ1 and HERG genes that encode potassium channels (rapid and slow) responsible for the occurrence of particular types of LQT syndrome. The study also attempted to prove that beta-actin is a good endogenous control when determining the expression of the studied genes.
Methods: The study enrolled six families whose members suffered from either LQT1 or LQT2, or were healthy. Examination of gene expression was achieved with quantitative PCR (QRT-PCR). Expression of the investigated genes was inferred from the analysis of the number of mRNA copies per 1 mg total RNA isolated from whole blood. On the basis of KCNQ1 gene expression profile, the presence of, or absence of, LQT1 could be confirmed.
Results and Conclusions: The study revealed a statistically significant difference (p = 0.031) between the number of KCNQ1 gene copies in patients and healthy controls. On the basis of HERG (KCNH2) gene expression profile, patients with LQT2 cannot be unequivocally differentiated from healthy subjects (p = 0.37).