Patient 6 is a male who is currently 2 years 7 months old. He was observed to have severe hypotonia in his infancy and developmental delay. He was incapable of lifting his head at the age of 5 months but could sit independently at 9 months; however, he exhibited a regression in development and was unable to walk independently. He also did not show any non-verbal communication skills and was unable to imitate or babble. Poor eye contact, head shaking, hand clapping and hand wringing were observed at the age of 1 year and 6 months. The patient displayed purposeful hand usage. He also presented recurrent, febrile or non-febrile, generalized tonic-clonic seizures at the age of 9 months. Topiramate, VPA and LEV were used but none of them showed a positive effect; this treatment was withdrawn at the age of 2 years. At present, the patient's daily seizures have been characterized as myoclonic. EEG findings obtained at the age of 10 months revealed spike-slow waves with bilateral-central-frontal involvement. MRI scans taken at the age of 15 months showed developmental malformation of the corpus callosum ().
Patient 3 is a female who is currently 4 years 4 months old. She showed some signs of developmental delay, such as lifting her head at the age of 5 months, sitting independently at the age of 9 months, and walking at the age of 2 years; she also did not exhibit any non-verbal communication skills and could not imitate actions or babble. Poor eye contact was observed at the age of 8 months. Hand clapping and hand wringing were observed when she was 1 year 6 months old. She demonstrated purposeful hand use, and at the age of 8 months, she experienced recurrent, febrile or non-febrile, generalized tonic-clonic seizures. She presented with status epilepticus, which later became absence status epilepticus at the age of 3 years 2 months. At this time, she was started on LEV medication but showed no response to it; subsequently, VPA was added to the treatment strategy at the age of 3 years 6 months, and the patient finally achieved a seizure-free status at the age of 4 years. Her EEG tests at the age of 15 months demonstrated sharp-slow synthetical waves at the left central and left parietal-frontal regions. EEG showed generalized sharp-slow waves and MRI findings indicated delayed myelination in the periventricular area at the age of 3 years 2 months ().