OBJECTIVETo investigate the clinical phenotypes and hereditary patterns of the generalized epilepsy with febrile seizures plus (GEFS+).

METHODSDetailed family trees were constructed by inquire and physical examinations for the probands of the 15 pedigrees of GEFS+. Some patients received electroencephalography, cranial CT or MRI examination. The seizures and epilepsy syndromes were classified according to the 2001 Seizure International Classification. The clinical data of GEFS+ were reviewed.

RESULTSThe 15 families consisted of 196 individuals. Seventy-five individuals were confirmed with epilepsy. The phenotypes of 64 out of the 75 patients with epilepsy conformed to GEFS+. The 64 patients included 38 males and 26 females (1 deceased) and there was no gender difference in the morbility of GEFS+. The age at onset was all in childhood. GEFS+ had a diversity of phenotypes. Febrile seizures (FS) were confirmed in 44 patients, FS and myoclonic seizure in 1, febrile seizures plus (FS+) in 13, FS+ and absence seizure in 2, FS+ and myoclonic seizure in 1, and FS+ and focal seizure in 3.

CONCLUSIONSThe heterogeneity of phenotypes and genetics may be the hallmarks of GEFS+. FS and FS+ are common phenotypes while FS+ and absence seizure, FS+ and myoclonic seizure, and FS+ and focal seizure are rare. If one of the parents is affected in a GEFS+ family, the susceptibility of their children to GEFS+ is the same no matter what gender of their children is. It is speculated that the hereditary pattern of GEFS+ conforms to autosomal dominant inheritance.