Lehnart et al. (10) found that the mouse ryanodine receptor 2 (RyR2) R2474S variant can specifically cause spontaneous generalized tonic–clonic seizures without arrhythmias, suggesting that the R2474S variant causing “leakage” of Ca2+ release channels in the brain can cause seizures in mice. The gene discussed is RYR2; the disease is cardiac arrhythmia.