Mutation information:
NumberExon/IntronNucleotide change Protein changeLocation Mutation typeConsequencesPhenotype InheritanceReference
68515c.2624C>T p.Thr875Met DIIS4MissenseP/O→N (81); G-LOF PEFS+Familial(Paternal,FS),P=10/10Escayg A.2000
SMEBNAWang JW.2012

Functional information:
NumberNucleotide changeProtein changeLocationPhenotypeFunctional defect type Details of the major biophysical abnormalities.Reference
16c.2624C>Tp.Thr875Met(T875M)DIIS4PEFS+ fG-LOF Small persistent current. Enhanced fast and slow inactivation that may result in reduced current density during long depolarization or repetitive stimulation.Lossin C.2002; Alekov AK.2001; Spampanato J.2001

Inheritance information:
NumberNucleotide changeProtein changeMutation type Proband's phenotype1st transmitter's phenotype Mosaic Affected generationsPenetranceReference
75c.2624C>Tp.Thr875Met T875M(DIIS4)MissensePEFS+FS(Paternal) 10/10Depienne C.2009

[c.2624C>T] Clinical description

Seizures were diagnosed in 12 living subjects, including one PEFS+, four GEFS+  (two with atonic seizures), and seven FS. Febrile seizures often lasted for 120 min, without focalization or motor deficiency (except in three relatives), and therefore did not meet complex FS criteria. The mean number of attacks was ~5 (range 2–20). Five family members presented with afebrile seizures associated with FS until their teenage years (mean 11 years). These seizures were generalized or hemicorporeal, tonic-clonic or atonic absence attacks.Neurological examination showed normal findings. Interictal electroencephalograms were normal except in three patients, in whom generalized spike-and-wave discharges arose a few years after the onset of FS.The first seizure occurred sooner in patients with both FS and other types of seizures (mean 5.8 months, range 1-7 months) than in those with FS only (mean 24 months, range 12–36 month).(Moulard B, et al. Am. J. Hum. Genet. 65:1396–1400, 1999. [10521305 ]).