Patient 2 is a female who is currently 5 years 9 months old. She exhibited a delay in achieving some developmental milestones, such as head lifting at 4 months, independent sitting at 1 year and independent walking at 2 years. She could say “baba,” or “mama” at the age of 1 year but exhibited regression in development with subsequent instances of only unconscious articulation. Nevertheless, she possessed non-verbal communication skills. Hand clapping was observed at 8 months. She displayed good eye contact as well as a purposeful hand use. She presented recurrent, febrile or non-febrile, generalized tonic-clonic seizures at 10 months; after being treated with LEV at the age of 15 months, she achieved a seizure-free status. Her seizure, which was characterized as a generalized tonic seizure without fever, relapsed at the age of 3 years and was treated with valproate (VPA) and LEV. She achieved a seizure-free status when she was 3.5 years old. EEG (15 months) findings revealed spike-and-slow waves with bilateral temporal and occipital involvement. MRI findings at the age of 10 months were normal ().
Patient 2 is a 2.5 years old girl presented with RTT-like ID. she displayed profound psychomotor retardation, with controlling head at 5 months, sitting alone at 8 months. She remained unable to walk independently and still had no speech at 2.5 years old. She developed stereotypic hand movements and bruxism at 2 years of age. No seizure was reported, but there was epileptiform discharge on EEG at age of 2 years. Brain MRI revealed high T1 and T2 signal at posterior horn of bilateral ventricle. A nonsense mutation, c.565C > T, p.Arg189*, of MEF2C was discovered, a known disease causing mutation ().