Mutation information:
NumberExon/IntronNucleotide change Protein changeLocation Mutation typeConsequencesPhenotype InheritanceReference
109921c.4057G>Cp.Val1353LeuDIIIS5MissenseN→N (32); LOF PEFS+Familial(Maternal, EP),P=8/9Wallace RH.2001
GEFS+NABennett CA.2017

Functional information:
NumberNucleotide changeProtein changeLocationPhenotypeFunctional defect type Details of the major biophysical abnormalities.Reference
31c.4057G>Cp.Val1353Leu(V1353L)DIIIS5PEFS+ fLOF No measurable sodium current.Lossin C.2003

Inheritance information:
NumberNucleotide changeProtein changeMutation type Proband's phenotype1st transmitter's phenotype Mosaic Affected generationsPenetranceReference
103c.4057G>Cp.Val1353Leu(DIIIS5)MissensePEFS+Unclassified EP(Maternal) 8/9Wallace RH.2001

[c.4057G>C] Clinical description

 The Israeli family  is of Ashkenazi origin and spans six generations. Twelve family members had seizures. In the two oldest members I-2 and III-3 seizures had occurred in childhood, but the data were insufficient to allow classification of the phenotype. Of the ten other family members who had seizures, three had FS with onset at age 9-13 months and that terminated by age one-four years, with one-seven attacks each, and five had FS+ with onset at age 9-24 months and that terminated at age 5-41 years, with 2-15 attacks each. Seizures during childhood were a mixture of FS and afebrile tonic-clonic seizures, whereas the rarely occurring seizures during teenage and adult years were all afebrile. Subject V-16 had a more severe phenotype, with ~20 febrile seizures at age six months-five years, ten afebrile tonic-clonic seizures at age 5-15 years, and occasional complex partial seizures associated with mild learning difficulties. She was classified as having FS+ and complex partial seizures. Her older sister, V-15, had typical FS+, but their younger brother, V-17, had no FS but had two afebrile tonic-clonic seizures at ages 12 years 6 months and 14 years. For purposes of linkage analysis, he was regarded as affected, although he had only afebrile tonic-clonic seizures. All affected subjects were of normal or superior intellect, except V-16 (see above), and all had a normal neurological examination. Electroencephalography (EEG) studies had been performed infrequently during the active phase of the epilepsy, and the results usually either were normal or were reported as showing generalized discharges(Wallace RH, et al. Am J Hum Genet. 2001 Apr;68(4):859-65.[11254444]).