A novel mutation of KCNQ3 (c.925T -> C) in a Japanese family with benign familial neonatal convulsions

At present, only one mutation of KCNQ3, a KCNQ potassium channel gene, has been identified as a cause of benign familial neonatal convulsions type 2 ( BFNC2). We found a T to C substitution (c.925T-->C) on one allele of affect ed individuals in a Japanese family with BFNC but not on 200 alleles from h ealthy subjects. c.925T-->C replaced Trp(309), a conserved residue within t he P-loop of the KCNQ potassium channel family that holds the channel pore open, with an Arg (W309R). We report c.925T-->C as the second mutation of K CNQ3 responsible for BFNC2.