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 Topiramate, VPA and LEV were used but none of them showed a positive effect; this treatment was withdrawn at the age of 2 years.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 7 is a female who is currently 2 years 5 months old. She experienced severe hypotonia at infancy and was observed to have developmental delay. She was incapable of both lifting her head at the age of 7 months and sitting independently at the age of 2 years; she was also unable to walk independently, demonstrated no non-verbal communication skills, and was unable to imitate or babble. Poor eye contact as well as head-shaking and hand-clapping behavior were observed at the age of 1 year. She did not display purposeful hand usage. She did not experience seizure. EEG test conducted at the age of 2 years revealed 2–3 Hz sharp-slow waves at the left parietal-occipital region. MRI scans taken at the age of 14 months showed malformation of the corpus callosum, delayed myelination and leukomalacia in the periventricular region ().