The data of a child with early-onset epileptic encephalopathy in Qilu Children′s Hospital of Shandong University in February 2020 were analyzed retrospectively.The child was a 4-month-old girl, who was admitted to the hospital because of " repeated convulsions for 4 months and feeding difficulty for 1 month" at the age of 4 months.The patient suffered from epilepsy 1 day after birth, and the epilepsy type was tonic seizures.Severe developmental retardation was observed in the patient.Electroencephalogram showed multifocal discharge, which then turned to hypsarrhythmia.The cranial imaging was negative.Feeding difficulty occurred at the age of 3 months.The genetic testing revealed a de novo heterozygous missense mutation in the FGF12 gene (Arg114His). Various antiepileptic drugs and ketogenic diet were ineffective.There was no attack in 2 months after adding Phenytoin.The child could eat on her own after seizure control, but there was no progress in intellectual and motor development.Mutations in the FGF12 gene lead to poor prognosis of early-onset epileptic encephalopathy, and the seizures are difficult to control.Sodium ion channel blockers such as Phenytoin should be used as soon as possible.

A retrospective analysis was performed on the clinical data of a case of intellectual developmental disorders with dysmorphic facies and behavioral abnormalities admitted in the Department of Neurology and Endocrinology, Children′s Hospital Affiliated to Shandong University in February 2020.The proband was a 3 years and 6 months old boy, who was hospitalized because of " convulsions for more than 1 year" . Physical examination revealed facial deformities.Gesell developmental schedule showed that adaptive and gross motor behavior development was severely retarded, and fine motor, language and personal-social behavior development was moderately retarded.Brain magnetic resonance imaging suggested schizencephaly.Electroencephalogram results indicated extensive discharges mainly in bilateral anterior head areas, and one myoclonic seizure was detected.Gene detection results disclosed the pathogenic variation of the proband, which was a heterozygote mutation (c.2480_2484del) in FBXO11 gene.High-throughput sequencing technology increases the possibility of identifying potential genetic mutations as the cause of disease.Patients with recurrent seizures, multi-malformation and general developmental delays should undergo gene detection in time to clarify the etiology.This technique can guide prenatal diagnosis and genetic counseling.