Familial cortical myoclonic tremor with epilepsy: A single syndromic classification for a group of pedigrees bearing common features

Abstract

Fifty Japanese and European families with cortical myoclonic tremor and epilepsy have been reported under various names. Unfamiliarity with the syndrome often leads to an initial misdiagnosis of essential tremor or progressive myoclonus epilepsy. A detailed overview of the literature is lacking and is the scope of this study. Disease characteristics are adult onset, distal action tremor and myoclonus, epileptic seizures, autosomal dominant inheritance, benign course, effectiveness of antiepileptic drugs, and possibly cognitive decline. A channelopathy is hypothesized to be the basis of the disease. Despite phenotypic and genetic differences between the Japanese and European pedigrees, the clinical and electrophysiological data point toward one syndrome. To avoid confusion in literature and possible misdiagnosis of patients, we propose to use one description and suggest "familial cortical myoclonic tremor with epilepsy" (FCMTE). In addition, we put forward diagnostic criteria to give a starting point from which to conduct genetic studies.

Remapping and mutation analysis of benign adult familial myoclonic epilepsy in a Japanese pedigree

“…1,2 Historically, various names have been given to the syndrome that show cortical myoclonic tremor and epilepsy: hereditary tremor with epileptiform seizures, 3 heredofamilial tremor and epilepsy, 4 cortical tremor, 5 familial essential myoclonus and epilepsy, 6 BAFME, 1 familial adult myoclonic epilepsy (FAME), 7 familial benign myoclonus epilepsy of adult onset, 8 familial cortical tremor with epilepsy, 9 autosomal dominant cortical myoclonus and epilepsy 10 and familial cortical myoclonic tremor with epilepsy (FCMTE). 11 Previous genetic studies, including our earlier report, 2 identified three different chromosomal loci, 8q 2,12 (BAFME, FCMTE1), 2p 10,13,14 (FCMTE2) and 5p 15 (FCMTE3) in Japanese, Italian and French pedigrees, respectively. The European patients seemed to show a more progressive disease course than Japanese patients.…”

“…Remapping and mutation analysis of BAFME S Mori et al Van Rootselaar et al 11 elucidated the diagnostic criteria of FCMTE. According to their diagnostic criteria, a member with myoclonic tremor, which is not accompanied by EEG changes and electrophysiological features of cortical reflex myoclonus (giant-SEPs, C-reflexes), is considered as probably affected, if at least one member of the family have cortical myoclonic tremor and at least one have epileptic attacks.…”

“…The European patients seemed to show a more progressive disease course than Japanese patients. 11 Compared with Japanese patients, the European patients also appear to be less susceptible to the effects of antiepileptic drugs. Worsening of epilepsy over the years leading to symptoms such as 'inability to use hands or legs' has been reported, especially in the European pedigrees.…”

Altered intrinsic brain activity in patients with familial cortical myoclonic tremor and epilepsy: An amplitude of low-frequency fluctuation study

“…Our findings indicated that the impairment in motor-related regions might be associated with tremulous movements. Impairments in motor-related areas are caused by a γ-aminobutyric acid (GABA) synaptic impairment [4,27]. Furthermore, the duration of tremor significantly influenced the ALFF in the frontal lobe (Fig.…”

Simultaneous EMG‐functional MRI recordings can directly relate hyperkinetic movements to brain activity

“…This existing knowledge enables the validation of simultaneous EMG-fMRI recordings and analysis, employing r-EMG, in particular, in patients with a movement disorder. FCMTE is an autosomal dominantly inherited disorder, characterized by a continuous fine distal action myoclonus of known cortical origin [Ikeda et al, 1990;Striano et al, 2005;van Rootselaar et al, 2005]. Patients with FMCTE show increased cortical hyperexcitability as represented by features of cortical reflex myoclonus like a giant cortical sensory evoked potential (g-SEP) induced by distal nerve stimulation [van Rootselaar et al, 2005].…”