While a contribution of the SCN2A variant to the neurodevelopmental phenotype of patient B cannot be fully excluded, we find a major impact unlikely for the following reasons: (i) developmental delay in SCN2A‐related diseases is associated with epileptic activity (Sanders et al, 2018; Wolff et al, 2019) and our patient never had apparent seizures or pathological EEG; (ii) SCN2A‐related diseases are normally autosomal dominant and caused by de novo pathogenic variants, except for benign familial neonatal or infantile seizures (OMIM #607745, Wolff et al, 2017). This evidence concerns the gene SCN2A and Seizure.