KCNQ2 and developmental and epileptic encephalopathy: Heterozygous missense variants in Kv7.2 are responsible for epileptic diseases characterized by a highly heterogeneous genetic transmission and clinical severity, ranging from autosomal-dominant Benign Familial Neonatal Seizures (BFNS) to sporadic cases of severe epileptic and developmental encephalopathy (DEE).