Epilepsy was referred in all of the six girls but: a) the age of seizures onset was very variable, occurring later than expected for STXBP1-EE (on average at six weeks) [25] in three out of six patients; b) the type of crisis was heterogeneous and only in one patient (No. 4) the onset was typical for West syndrome; c) the pharmacological response varied from drug resistance to responsiveness. Here, STXBP1 is linked to epilepsy.