Fig. 2

Gene sequencing of four case and their families with Poirier Bienvenu neurodevelopmental syndrome related to CSNK2B gene variant. Family 1 (Case 1): c.175 + 1G > A splicing mutation (arrow) in CSNK2B gene was detected, and both parents and brother are wild-type; Family 2 (Case 2): c.73–2 A > G splicing variant (arrow) in CSNK2B gene was detected. the parents and younger brother are wild-type; Family 3 (Case 3): c.291 + 1G > A splicing variant (arrow) in CSNK2B gene was detected, and the parents are wild-type; Family 4 (Case 4): c.481delA frameshift variant (arrow) in CSNK2B gene was detected, and the parents are wild-type. GTCS: generalized tonic-clonic seizure, JME: positive myoclonic seizure, AS: absence seizure