SCN2A and neurodevelopmental disorder: Mosaicism in the proband has been reported in other genes such as PCDH19 (8.3%, 6/73), SCN1A (1.3%, 4/320), SCN2A (6.4%, 7/110), and CDKL5 (8.8%, 8/91), according to a recent large‐scale study of epilepsy‐related neurodevelopmental disorders.29