By 8 weeks of age, while ShScramble-infected mice had normal ECGs (Figure 5b), up to 78% of Znf219-knockdown mice had more prominent arrhythmias (Figure 5b and Figure S7, supplementary material), with episodes of bradycardia and tachycardia, suggesting a progressive phenotype. The gene discussed is ZNF219; the disease is cardiac arrhythmia.