Table 1 Comparison table of the clinical characteristics between case 1 and case 2

Seizure onset

3 months, triggered after immunization

3 months, triggered after immunization

Seizure type

Generalized tonic clonic seizures, absence seizure

Generalized tonic clonic seizures, myoclonic, and status epilepticus

Family history

None

None

Developmental

Global developmental delay

Global developmental delay

Neurologic status

Normal

Increased physiological reflexes in all extremities

Electroencephalography features

Diffuse epileptiform abnormality on a normal background

Abnormal epileptiform with a normal background

Radiology

Head magnetic resonance imaging result:

Cerebral atrophy, bilateral frontal subarachnoid enlargement, bilateral occipital lobe polymicrogyria, and neuroglial cyst in right temporal lobe

Head computed tomography scan result:

Subdural hygroma in the bilateral frontoparietal region

Genetic testing

Heterozygous deletion NC_000002.12:g.165811316_166364199delinsTGTACACTA at 2q24.3 spans across three genes (TTC21B, SCN1A, and SCN9A)

Heterozygous mutation in exon 9 of the SCN1A gene, c.4003-2A > G (p.?)

Inheritance

Unknown

De novo

Outcome

Seizure free for 3 months with valproic acid (40mg/kg per day), phenobarbital (2.5mg/kg per 12 hours), and (levetiracetam 27mg/kg per day), but later, the patient had generalized seizure induced by fever with duration less than 5 minutes. Electroencephalography evaluation showed epileptiform irritative abnormality still persisted

Seizure decreased to one seizure per year, with a less than 1 minute duration after given valproic acid (30 mg/kg weight per day) and clonazepam (0.04 mg/kg body weight per day)