The molecular genetics of arrhythmias.

It was only ten years ago that mutations in ion channel genes were first described in patients with the long QT syndrome (LQTS) [1]. Since then, mutations in a total of eight different sarcolemmal ion channel subunit genes (KCNQ1, KCNH2, KCNE1, KCNE2, SCN5A, KCNJ2, HCN4, CACNA1C), two genes encoding sarcoplasmic reticulum (SR) Ca handling proteins (RYR2, CASQ2), and an anchoring protein gene (ANK2) have been linked to a range of primary arrhythmia syndromes. The recognition of abnormal function of these genes in the inherited arrhythmia syndromes has provided remarkable insight into mechanisms of arrhythmias not only in these uncommon syndromes, but has also had very important implications for arrhythmia mechanisms and management more generally. It is therefore very opportune that Cardiovascular Research dedicates this spotlight issue to this topic. In this issue, a series of reviews summarizes the current state-ofthe-art, and a number of original papers present new data on various aspects of cardiac arrhythmia genetics.