[Benign familial neonatal convulsions: molecular pathology and diagnosis]

Benign familial neonatal convulsions are a rare monogenic form of idiopathic epilepsy characterized by the onset of frequent brief seizures after the second day of life. The seizures disappear spontaneously within a few weeks, but recurrent seizures later in life are common. Linkage studies located genes to chromosome 20q13.3 and 8q24, and the voltage-gated potassium channels KCNQ2 and KCNQ3 were recently identified. Since then, several mutations have been found leading to haplosufficiency of the ion channel. Functional studies showed that KCNQ2 and KCNQ3 are able to contribute to a heteromeric channel exhibiting kinetic and pharmacological properties similar to those of the native M current, the latter playing an important role in the regulation of neuronal excitability. This overview presents a summary of the molecular, genetic, and electrophysiological findings and discusses them with respect to their clinical relevance.