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Benign Familial Neonatal Convulsions, BFNC - KCNQ2, KCNQ3

Clinical Features

Benign Familial Neonatal Convulsion Syndrome (BFNC) is characterized by short, tonic-clonic seizures that stereotypically begin two or three days after birth only to go into spontaneous remission several weeks later. Some affected patients (ca. 10%) suffer afebrile, Rolandic seizures later in childhood. The limited occurrence in the first weeks of life can be explained by the fact that, in this phase, the GABA system is still excitatory and the main inhibitor in the central nervous system passes through the so-called M-potassium ion channel. The ion channels KCNQ2 and KCNQ3 constitute this M-potassium ion channel, which is responsible for the inhibition of repetitive action potential.

Genetic Information

The pattern of inheritance is autosomal dominant with high penetrance. The cause of BFNC has been attributed to mutations in the KCNQ2 (Potassium channel, voltage gated, KQT-like subfamily, member 2, 20q13.3) and KCNQ3 (Potassium channel, voltage gated, KQT-like subfamily, member 3, 8q24) genes.

Prevalence

Rare

Diagnostic