KCNQ3

Benign familial neonatal seizures

A mutation in the KCNQ3 gene has been identified in some people with benign familial neonatal seizures (BFNS), a condition characterized by recurrent seizures in newborn babies. The seizures begin around day 3 of life and usually go away within 1 to 4 months. At least three mutations have been identified in people with this condition, and these mutations change single protein building blocks (amino acids) in the KCNQ3 protein. As a result of these mutations, the M-current is reduced. Researchers believe that a reduction of the current by 25 percent is enough to cause BFNS. A reduced M-current leads to excessive excitability of neurons, which is known to cause seizures. It is unclear why the seizures stop around the age of 4 months. It has been suggested that potassium channels formed from the KCNQ2 and KCNQ3 proteins play a major role in preventing excessive excitability of neurons in newborns, but other mechanisms develop during infancy.