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Ding Y, Cen Z, Zheng Y, Qiu X, Ye Y, Chen X, Hu L, Wang B, Wang Z, Yin H, Shen C, Ming W, Ge Y, Xie F, Yang D, Ouyang Z, Wang H, Wu S, Ding M, Wang S, Luo W. Seizures and electrophysiological features in familial cortical myoclonic tremor with epilepsy 1. Ann Clin Transl Neurol 2024; 11:414-423. [PMID: 38059543 PMCID: PMC10863925 DOI: 10.1002/acn3.51961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/09/2023] [Accepted: 11/11/2023] [Indexed: 12/08/2023] Open
Abstract
OBJECTIVES To investigate and characterize epileptic seizures and electrophysiological features of familial cortical myoclonic tremor with epilepsy (FCMTE) type 1 patients in a large Chinese cohort. METHODS We systematically evaluated 125 FCMTEtype 1 patients carrying the pentanucleotide (TTTCA) repeat expansion in the SAMD12 gene in China. RESULTS Among the 28 probands, epileptic seizures (96.4%, 27/28) were the most common reason for an initial clinic visit. Ninety-seven (77.6%, 97/125) patients had experienced seizures. The seizures onset age was 36.5 ± 9.0 years, which was 6.9 years later than cortical tremors. The seizures were largely rare (<1/year, 58.8%) and occasional (1-6/year, 37.1%). Prolonged prodromes were reported in 57.7% (56/97). Thirty-one patients (24.8%, 31/125) reported photosensitivity history, and 79.5% (31/39) had a photoparoxysmal response. Interictal epileptiform discharges (IEDs) were recorded in 69.1% (56/81) of patients. Thirty-three patients showed generalized IEDs and 72.7% (24/33) were occipitally dominant, while 23 patients presented with focal IEDs with 65.2% (15/23) taking place over the occipital lobe. Overnight EEG of FCMTE patients displayed paradoxical sleep-wake fluctuation, with a higher average IED index of 0.82 ± 0.88/min during wakefulness and a lower IED index of 0.04 ± 0.06/min during non-rapid eye movement sleep stages I-II. INTERPRETATION FCMTE type 1 has a benign course of epilepsy and distinct clinical and electrophysiological features. In addition to a positive family history and cortical myoclonus tremor, the seizure prodromes, specific seizure triggers, photosensitivity, distribution of IEDs, and unique fluctuations during sleep-wake cycle are cues for proper genetic testing and an early diagnosis of FCMTE.
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Affiliation(s)
- Yao Ding
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Zhidong Cen
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Yang Zheng
- Department of NeurologyZhejiang Chinese Medical University First Affiliated HospitalHangzhouZhejiangChina
| | - Xia Qiu
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Yumao Ye
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Department of NeurologyQingyuan County People's HospitalLishuiZhejiangChina
| | - Xinhui Chen
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Lingli Hu
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Bo Wang
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Zhongjin Wang
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Houmin Yin
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Chunhong Shen
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Wenjie Ming
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Yi Ge
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Fei Xie
- Department of NeurologySir Run Run Shaw Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Dehao Yang
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Zhiyuan Ouyang
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Haotian Wang
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Sheng Wu
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Meiping Ding
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Shuang Wang
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
- Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
| | - Wei Luo
- Department of NeurologySecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhouZhejiangChina
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Cuccurullo C, Striano P, Coppola A. Familial Adult Myoclonus Epilepsy: A Non-Coding Repeat Expansion Disorder of Cerebellar-Thalamic-Cortical Loop. Cells 2023; 12:1617. [PMID: 37371086 DOI: 10.3390/cells12121617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/07/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Familial adult myoclonus Epilepsy (FAME) is a non-coding repeat expansion disorder that has been reported under different acronyms and initially linked to four main loci: FAME1 (8q23.3-q24.1), FAME 2 (2p11.1-q12.1), FAME3 (5p15.31-p15.1), and FAME4 (3q26.32-3q28). To date, it is known that the genetic mechanism underlying FAME consists of the expansion of similar non-coding pentanucleotide repeats, TTTCA and TTTTA, in different genes. FAME is characterized by cortical tremor and myoclonus usually manifesting within the second decade of life, and infrequent seizures by the third or fourth decade. Cortical tremor is the core feature of FAME and is considered part of a spectrum of cortical myoclonus. Neurophysiological investigations as jerk-locked back averaging (JLBA) and corticomuscular coherence analysis, giant somatosensory evoked potentials (SEPs), and the presence of long-latency reflex I (or C reflex) at rest support cortical tremor as the result of the sensorimotor cortex hyperexcitability. Furthermore, the application of transcranial magnetic stimulation (TMS) protocols in FAME patients has recently shown that inhibitory circuits are also altered within the primary somatosensory cortex and the concomitant involvement of subcortical networks. Moreover, neuroimaging studies and postmortem autoptic studies indicate cerebellar alterations and abnormal functional connectivity between the cerebellum and cerebrum in FAME. Accordingly, the pathophysiological mechanism underlying FAME has been hypothesized to reside in decreased sensorimotor cortical inhibition through dysfunction of the cerebellar-thalamic-cortical loop, secondary to primary cerebellar pathology. In this context, the non-coding pentameric expansions have been proposed to cause cerebellar damage through an RNA-mediated toxicity mechanism. The elucidation of the underlying pathological mechanisms of FAME paves the way to novel therapeutic possibilities, such as RNA-targeting treatments, possibly applicable to other neurodegenerative non-coding disorders.
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Affiliation(s)
- Claudia Cuccurullo
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, 16126 Genova, Italy
| | - Antonietta Coppola
- Department of Neuroscience, Reproductive Sciences and Odontostomatology, Federico II University of Naples, 80131 Naples, Italy
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Baykan B, Franceschetti S, Canafoglia L, Cavalleri GL, Michelucci R, Scheffer IE. Differential diagnosis of familial adult myoclonic epilepsy. Epilepsia 2023. [PMID: 36751956 DOI: 10.1111/epi.17536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 01/27/2023] [Accepted: 02/06/2023] [Indexed: 02/09/2023]
Abstract
OBJECTIVE Familial adult myoclonic epilepsy (FAME) is an under-recognized disorder characterized by cortical myoclonus, generalized tonic-clonic seizures, and additional clinical symptoms, which vary depending on the FAME subtype. FAME is caused by pentanucleotide repeat expansions of intronic TTTCA/TTTTA in different genes. FAME should be distinguished from a range of differential diagnoses. METHODS The differential diagnoses and frequent presentations leading to misdiagnosis of FAME were investigated from the available literature and reported based on an expert opinion survey. RESULTS The phenotypic features of FAME, including generalized tonic-clonic and myoclonic seizures, are also seen in other epilepsy syndromes, such as juvenile myoclonic epilepsy, with a resultant risk of misdiagnosis and lack of identification of the underlying cause. Cortical myoclonus may mimic essential tremor or drug-induced tremor. In younger individuals, the differential diagnosis includes progressive myoclonus epilepsies (PMEs), such as Unverricht-Lundborg disease, whereas, in adulthood, late-onset variants of PMEs, such as sialidoses, myoclonus epilepsy, and ataxia due to potassium channel pathogenic variants should be considered. PMEs may also be suggested by cognitive impairment, cerebellar signs, or psychiatric disorders. Electroencephalography (EEG) may show similarities to other idiopathic generalized epilepsies or PMEs, with generalized spike-wave activity. Signs of cortical hyperexcitability may be seen, such as an increased amplitude of somatosensory evoked potentials or enhanced cortical reflex to sensory stimuli, together with the neurophysiological pattern of the movement disorder. SIGNIFICANCE Recognition of FAME will inform prognostic and genetic counseling and diagnosis of the insidious progression, which may occur in older individuals who show mild cognitive deterioration. Distinguishing FAME from other disorders in individuals or families with this constellation of symptoms is essential to allow the identification of underlying etiology.
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Affiliation(s)
- Betul Baykan
- Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey.,EMAR Medical Center, Istanbul, Turkey
| | - Silvana Franceschetti
- Department of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Laura Canafoglia
- Department of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Gianpiero L Cavalleri
- The School of Pharmacy and Biomolecular Sciences, The Royal College of Surgeons in Ireland, Dublin, Ireland.,The Science Foundation Ireland, FutureNeuro Centre of Excellence, Dublin, Ireland
| | - Roberto Michelucci
- Unit of Neurology and Epileptology, Bellaria Hospital, IRCCS - Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Ingrid E Scheffer
- Austin and Royal Children's Hospital, Florey and Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
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van den Ende T, Sharifi S, van der Salm SMA, van Rootselaar AF. Familial Cortical Myoclonic Tremor and Epilepsy, an Enigmatic Disorder: From Phenotypes to Pathophysiology and Genetics. A Systematic Review. Tremor Other Hyperkinet Mov (N Y) 2018; 8:503. [PMID: 29416935 PMCID: PMC5801339 DOI: 10.7916/d85155wj] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 01/02/2018] [Indexed: 02/06/2023] Open
Abstract
Background Autosomal dominant familial cortical myoclonic tremor and epilepsy (FCMTE) is characterized by distal tremulous myoclonus, generalized seizures, and signs of cortical reflex myoclonus. FCMTE has been described in over 100 pedigrees worldwide, under several different names and acronyms. Pathological changes have been located in the cerebellum. This systematic review discusses the clinical spectrum, treatment, pathophysiology, and genetic findings. Methods We carried out a PubMed search, using a combination of the following search terms: cortical tremor, myoclonus, epilepsy, benign course, adult onset, familial, and autosomal dominant; this resulted in a total of 77 studies (761 patients; 126 pedigrees) fulfilling the inclusion and exclusion criteria. Results Phenotypic differences across pedigrees exist, possibly related to underlying genetic differences. A "benign" phenotype has been described in several Japanese families and pedigrees linked to 8q (FCMTE1). French patients (5p linkage; FCMTE3) exhibit more severe progression, and in Japanese/Chinese pedigrees (with unknown linkage) anticipation has been suggested. Preferred treatment is with valproate (mind teratogenicity), levetiracetam, and/or clonazepam. Several genes have been identified, which differ in potential pathogenicity. Discussion Based on the core features (above), the syndrome can be considered a distinct clinical entity. Clinical features may also include proximal myoclonus and mild progression with aging. Valproate or levetiracetam, with or without clonazepam, reduces symptoms. FCMTE is a heterogeneous disorder, and likely to include a variety of different conditions with mutations of different genes. Distinct phenotypic traits might reflect different genetic mutations. Genes involved in Purkinje cell outgrowth or those encoding for ion channels or neurotransmitters seem good candidate genes.
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Affiliation(s)
- Tom van den Ende
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sarvi Sharifi
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
| | - Sandra M. A. van der Salm
- Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center, Utrecht, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Zwolle, The Netherlands
| | - Anne-Fleur van Rootselaar
- Department of Neurology and Clinical Neurophysiology, Amsterdam Neuroscience, Academic Medical Center, Amsterdam, The Netherlands
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