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 3 is a 23-month-old girl who presented with RTT-like features. Feeding difficulties caused concern at 3 months of age. No epilepsy was observed, though she had medical history of febrile convulsions at 9 months old. There was significant delay in her developmental milestones, without obvious retrogression. She could sit alone at 1 year old, and walk at 23 months of age, with abnormal gaits. Unmeaningful language began at 12 months. She also presented with poor eye contact, stereotypic actions, breathing disturbance, and sleeping abnormalities. She suffered from recurrent respiratory infections frequently after 15 months of age. MRI revealed hypomyelination at 1 year and 10 months of age. A novel nonsense mutation, c.334G > T, p.Glu112*, in MEF2C was identified.