Electroclinical features of a family with SCN1A loss-of-function mutation associated with simple febrile seizures

We report electro-clinical features of a large family composed by 35 members over four generations in which we recently identified a missense mutation (M145T) of SCN1A gene. Among 14 affected individuals, 13 alive members (7 males, mean age 36.6+20.4) had febrile seizures (FS) until the age of six. In two of the three patients who later developed temporal lobe epilepsy (TLE), the MRI study revealed mesial temporal sclerosis. Our findings illustrate that SCN1A mutations can cause simple FS associated with TLE, which differ from the characteristic clinical spectrum of GEFS+. It is questionable if this unusual phenotype might be at least in part related to the fact that M145T is the first missense mutation found in DIS1 of SCN1A.