Increased seizure susceptibility in Cdkl5 deletion and knock-in female mice. (A, B) Reduced latencies to first jerk and generalized clonic seizures were observed in Cdkl5^exon6−/+ females after an i.p. injection of 80 mg/kg PTZ over the course of a 30 min trial. (C, D) Reduced latencies to first jerk and generalized clonic seizures were observed in Cdkl5^R59X−/+ females after an i.p. injection of 80 mg/kg PTZ over the course of a 30 min trial. Data are expressed as mean ± S.E.M. ^*P < 0.05 indicates when the Cdkl5 mutant mice differ from wild-type, sex-matched littermate controls.