To further examine whether ATF3 overexpression affects ion channel genes related to LQTS, quantitative PCR was performed on seven representative genes (kcnq1.1, kcnh2b, cacna1c, calm1a, calm1b, kcnj2a, and kcnj2b) using cardiac cDNA from 4-month post-fertilization (mpf) zebrafish hearts (Fig. 4h). The gene discussed is CACNA1C; the disease is familial long QT syndrome.