These data are similar to previous work with the SCN1B‐p.Cys121Trp variant, also located in the Ig loop domain, showing normal cell surface expression, but LOF in terms of sodium current (INa) modulation7, 20 and for which a homozygous mouse model shows a phenotype that is similar to Scn1b null mice.21 Importantly, our results provide new information about autosomal recessive inheritance in epilepsy (reviewed in 22) and suggest reconsideration of the linkage of SCN1B variants to early infantile DEE rather than to EIEE or DS. The gene discussed is SCN1B; the disease is epilepsy.