A five-base pair insertion in the KCNQ2 potassium channel gene, which abolishes measurable potassium currents, was identified in a large pedigree with benign familial neonatal convulsions.
A mutation in the KCNQ2 potassium channel gene impairs potassium-dependent repolarization, likely causing benign familial neonatal convulsions.
Benign familial neonatal convulsions (BFNC) is an autosomal dominant epilepsy of infancy, with loci mapped to human chromosomes 20q13.3 and 8q24. By positional cloning, a potassium channel gene (KCNQ2) located on 20q13.3 was isolated and found to be expressed in brain. Expression of KCNQ2 in frog (Xenopus laevis) oocytes led to potassium-selective currents that activated slowly with depolarization. In a large pedigree with BFNC, a five-base pair insertion would delete more than 300 amino acids from the KCNQ2 carboxyl terminus. Expression of the mutant channel did not yield measurable currents. Thus, impairment of potassium-dependent repolarization is likely to cause this age-specific epileptic syndrome.
Biervert et al. (Fri,) conducted a other in Benign familial neonatal convulsions (BFNC). KCNQ2 mutation (five-base pair insertion) vs. Wild-type KCNQ2 was evaluated on Potassium-selective currents. A five-base pair insertion in the KCNQ2 potassium channel gene, which abolishes measurable potassium currents, was identified in a large pedigree with benign familial neonatal convulsions.