The genetic causes of febrile seizures are still being researched with several genetic associations being identified in the article titled “Molecular genetics of febrile seizures“. In particular, six (6) susceptibility Febrile Seizure (FS) loci have been identified on chromosomes 8q13–q21 (FEB1), 19p (FEB2), 2q23–q24 (FEB3), 5q14–q15 (FEB4), 6q22–q24 (FEB5), and 18p11 (FEB6).
Furthermore, there is evidence of familial history being a contributing factor (e.g. parents with a history of febrile seizures) with one US study reporting that 17% of parents and 22% of siblings of children with febrile seizures were also affected. Our own Seizure Report results are that 27% of reported seizures are for children who have a family history of them (i.e. a parent or sibling suffered from febrile seizures).
And while there is a global average of anywhere from 2% to 5% of children experiencing a febrile seizure before the age of five (5) the frequency of occurrence is 7% in Japan and as high as 14% in the Mariana Islands.