Finding both GOF and LOF variants is common in dosage-sensitive genes including many genetic etiologies implicated in the epilepsies, such as SCN2A or SCN8A. 34,35 In KCNQ2-associated diseases, the use of antiepileptic drugs effective for LOF variants of KCNQ2 is associated with poor outcomes in patients with a GOF variant.36 This evidence concerns the gene SCN2A and epilepsy.