Recently, several gain of function mutations in KCNT1 gene (coding for Kca4.1, a sodium-activated potassium channel also named Slo2.2 or SLACK) have been identified in patients with two different types of epilepsy occurring in infancy or childhood: Malignant Migrating Partial Seizures of Infancy (MMPSI; also called Epilepsy of Infancy with Migrating Focal Seizures, EIMFS; prevalence: <1/1000,000) and Autosomal Dominant Nocturnal Frontal Lobe Epilepsy (ADNFLE; prevalence: over 100 reported families; Lim et al., 2016; Tang et al., 2016). This evidence concerns the gene KCNT1 and malignant migrating partial seizures of infancy.