Table 2.

Clinical characteristics of three affected patients.

	IV-1	IV-4	IV-6
Sex/Age	M/22 y 11 months	M/13 y 8 months	F/4 y 10 months
Age at examination	19 y	9 y	2 y
Past medical history	Hypotonia in infancy	Hypotonia in infancy	Hypotonia in infancy
Seizure
Onset age	5 y	6 months	3 months
Type	Generalized tonic-clonic Atypical absence	Focal impaired awareness Secondary generalized tonic	Generalized tonic Focal impaired awareness
Frequency	10–15/day at the beginning → 1–2/month at the time of visiting	1/month	Under control with medication
Antiseizure medications	Valproate, clonazapem, lacosamide, levetiracetam	Valproate	Levetiracetam
Delayed development	Severe global delay	Severe global delay	Moderate motor and adaptive delay Severe language delay
Psychosocial state	Severe intellectual disability Hyperactivity	Severe intellectual disability Hyperactivity	Severe cognitive dysfunction Behavioral problem is not proved yet.
Abnormal findings on neurologic examination	Slurred speech Clumsy hand movement Mild ataxic gait	Slurred speech Clumsy hand movement Mild ataxic gait	Hypotonia Mild ataxic gait
Disease course	Static	Static	Progressive → Static
EEG results	Sharp wave in Rt. or Lt. F region Ictal—rhythmic theta in both FC regions	Spike in Rt. or both F regions Spike in Rt. T region Polyspikes in Rt. hemisphere	Spike in Lt. or both FC regions
Brain MRI findings	Mild cerebral atrophy HSI in the bilateral globus pallidi and dentate nucleus	Mild cerebral atrophy HSI in the bilateral globus pallidi and dentate nucleus Perisylvian polymicrogyria	HSI in the bilateral globus pallidi and dentate nucleus

F, frontal; FC, fronto-central; T, temporal; EEG, electroencephalography; MRI, magnetic resonance imaging; HSI, high signal intensity.