To investigate for the first time the natural history and long-term evolution of "familial cortical tremor, myoclonus, and epilepsy."We evaluated the clinical, electrophysiologic, and treatment data of 14 patients from three families linked to 2p11.1-q12.2. A simplified scale was used to score myoclonus severity. Electroencephalography (EEG) studies were reviewed for the evaluation of background activity, paroxysmal abnormalities, and photoparoxysmal response. Data were organized for age groups. Correlation and logistic regression analysis were performed.Patients' mean age was 47.8 ± 22.0 years (range 20-86 years). Mean age at disease onset was 20.2 ± 7.8 years (range 11-40 years); mean follow-up duration was 14.0 ± 5.8 years (range 7-28 years). Evaluation at different age groups revealed a gradual, progressive worsening of the myoclonus in 10 patients (71.4%). Two subjects aged >80 years showed myoclonus interfering with autonomous walking. Myoclonus severity was correlated with disease duration (p<0.001) and patients' age (p=0.001). Six patients (42.8%) experienced seizures, usually between the second and sixth decades of life. Evaluation of EEG long-term evolution revealed progressive slowing of background activity in parallel with the gradual worsening of myoclonus. In contrast, paroxysmal activity and photosensitivity were particularly evident during the intermediate phases of the disease. In addition, psychiatric and neuropsychological dysfunction occurred in more than one third of the patients.We provide data for a slight age-dependent progression and the presence of neuropsychiatric and neuropsychological dysfunction in this unique syndrome, for which the definition of familial or autosomal dominant cortical tremor, myoclonus, and epilepsy (FCTME/ADCME) seems to be, therefore, more appropriate.