Autosomal Dominant Cortical Tremor, Myoclonus, and Epilepsy Syndrome Mimicking Juvenile Myoclonic Epilepsy

Introduction: Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME) syndrome is a genetically heterogeneous and under-recognized disease characterized by tremulous movements mimicking essential tremor, myoclonus, and rare generalized tonic-clonic seizures. Here we described the clinical and electrophysiological features of three siblings with ADCME syndrome mimicking juvenile myoclonic epilepsy (JME).

Methods: Three siblings (two females and one male) diagnosed with ADCME were analyzed by electroencephalogram (EEG), somatosensory evoked potentials, and accelerometric recordings. The results were compared with 14 JME patients without tremor and 14 with essential tremor (ET).

Results: The shared features of the siblings were cortical tremor, myoclonia, epilepsy, migraine, and psychiatric symptoms. In all siblings, tremor had started before myoclonic epilepsy associated with 4-6 Hz generalized spike and wave discharges. The N20-P25 and P25-N35 amplitudes were substantially higher in the three siblings with ADCME. Although tremor frequencies were similar to those of the ET group, the siblings had mild interrupting low-amplitude myoclonus, suggestive of cortical tremor, in the accelerometric analysis.

Conclusion: We presented a detailed clinical evaluation with electrophysiological confirmation of ADCME syndrome in a Turkish family. This rare clinical picture might be misdiagnosed as JME and should be kept in mind to ensure correct diagnosis and to provide a homogenous group for genetic studies.