The proteins SV2A and SV2B regulate presynaptic Ca2+ accumulation, action potential-dependent neurotransmitter release in e.g., hippocampal neurons and their absence induces epilepsy e.g., SV2A deficiency showed elevated seizure vulnerability in an SV2A knockout model of zebrafish (Janz et al., 1999; Sills, 2010; Zhang et al., 2022). The gene discussed is SV2B; the disease is epilepsy.