Patient 1 is a girl aged 5 years and 9 months, the first child of a healthy nonconsanguineous couple. Her psychomotor milestones were profoundly delayed, with raising head at 8 months, sitting alone at 1 year old, and still unable to walk by herself at 5 years and 9 months. Poor eye contact, hand clapping, hand wringing and bruxism were observed at 1 year old, followed by deterioration of hand skills. Epileptic attack occurred at 20 months old, and she responded to valproate (VPA), oxcarbazepine (OXC), and topiramate (TPM) combined therapy. Seizure free was achieved at 5.5 years old. EEG demonstrated spike-slow waves at right medial and posterior temporal, with generalization. MRI (1 year old) revealed enlargement of frontal subarachnoid space. Above manifestations led to the diagnosis of typical RTT. However, mutational analysis of MECP2, CDKL5 and FOXG1 was negative. Through this study, a de novo missense MEF2C mutation, c.48C > G, p.Asn16Lys, was identified, which was a novel mutation.
Patient 4 is a female who is currently 2 years 10 months old. Developmental delay was observed with regard to lifting of her head only at the age of 7 months and the ability to sit independently only at the age of 1 year; she also did not have the ability to walk independently and did not display any non-verbal communication skills. Although she could say the words “baba” or “mama” at the age of 2 years, she displayed a regression in development and only showed signs of unconscious articulation subsequently. Poor eye contact, head shaking, hand clapping, hand wringing, and bruxism were observed at the age of 1 year 3 months. Purposeful hand use was presented and retained. She experienced recurrent, febrile or non-febrile, generalized tonic-clonic seizures at the age of 11 months. Dystonic seizure occurred at 14 months. LEV was administered at the age of 16 months and the patient achieved seizure-free status at the age of 2.5 years. Her EEG (15 months and 2.5 years) and MRI (3 year) findings revealed normal findings ().