• convulsions
• pericentric inversion
• chromosome 5

• BFNC, benign familial neonatal convulsions
• BFIC, benign familial infantile convulsions

We describe a family in whom a pericentric inversion of chromosome 5 segregates with benign familial neonatal convulsions (BFNC). BFNC is an autosomal dominant form of epilepsy characterised by spontaneous partial or generalised clonic convulsions beginning within the first months of life. Seizures usually disappear by the age of 6 months; intercritical electroencephalogram and subsequent psychomotor development are normal. BFNC loci have been mapped to human chromosomes 20q13.3 (BFNC1) and 8q24 (BFNC2), based on linkage analysis.^{1, 2} Recently, two potassium channel genes (KCNQ2 and KCNQ3), located in these two regions, were shown to be mutated in BFNC1 and BFNC2, respectively.^{3, 4}

We report a family with BFNC and a pericentric inversion of chromosome 5 cosegregating with BFNC. Fluorescence in situ hybridisation (FISH) experiments were performed to define the breakpoints at YAC level. The linkage of BFNC to KCNQ2 and mutations in the KCNQ3 gene were excluded. This report raises the possibility of a new locus for BFNC on chromosome 5.