With Vglut2:Ndufs4cKO mice, the lethality was associated with severe motor and respiratory alterations, whereas with Gad2:Ndufs4cKO mice, sudden unexpected death was associated with epilepsy (SUDEP) (Abdel-Mannan et al., 2019; Manolis et al., 2019; DeGiorgio et al., 2019) with no overt clinical alteration beyond the weight loss. The gene discussed is GAD2; the disease is epilepsy.