The electroencephalogram in acetazolamide‐responsive periodic ataxia

Neufeld, Miriam Y.; Nisipeanu, P.; Chistik, Vladimir; Korczyn, Amos D.

doi:10.1002/mds.870110312

Cited by 17 publications

(3 citation statements)

References 27 publications

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“…The prevalence of epilepsy (Rajakulendran et al 2010) and EEG abnormalities (Neufeld et al 1996) in individuals with clinical and genetically confirmed EA2 is higher than the background population, suggesting that genetic variations in CACNA1A may be a potential susceptibility factor in human epilepsy.…”

Section: Dominant Mutations In Ca V 21 Cause Episodic Ataxia Type 2 mentioning

confidence: 99%

The Role of Calcium Channels in Epilepsy

Rajakulendran

Hanna

2016

Cold Spring Harb Perspect Med

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A central theme in the quest to unravel the genetic basis of epilepsy has been the effort to elucidate the roles played by inherited defects in ion channels. The ubiquitous expression of voltage-gated calcium channels (VGCCs) throughout the central nervous system (CNS), along with their involvement in fundamental processes, such as neuronal excitability and synaptic transmission, has made them attractive candidates. Recent insights provided by the identification of mutations in the P/Q-type calcium channel in humans and rodents with epilepsy and the finding of thalamic T-type calcium channel dysfunction in the absence of seizures have raised expectations of a causal role of calcium channels in the polygenic inheritance of idiopathic epilepsy. In this review, we consider how genetic variation in neuronal VGCCs may influence the development of epilepsy.

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Section: Dominant Mutations In Ca V 21 Cause Episodic Ataxia Type 2 mentioning

confidence: 99%

The Role of Calcium Channels in Epilepsy

Rajakulendran

Hanna

2016

Cold Spring Harb Perspect Med

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“…Typically, patients with EA-2 have longer duration attacks lasting hours and also have interictal nystagmus. There is striking variability in the clinical symptoms and signs with various mutations in CACNA1A including allelic disorders SCA-6 (MIM# 183086) and familial hemiplegic migraine (MIM# 141500, Ophoff et al, 1996, Yue et al, 1997 (Neufeld et al, 1996) with epilepsy reported in both EA-1 (Zuberi et al, 1999, Eunson et al, 2000 and EA-2 (Zasorin et al, 1983, Jouvenceau et al, 2001, Jen et al, 2004.…”

Section: Introductionmentioning

confidence: 99%

A novel mutation in KCNA1 causes episodic ataxia without myokymia

et al. 2004

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We describe a unique family in which several individual are affected with episodes of ataxia that best fit the phenotype of episodic ataxia type 2 (EA2). All of the affected family members had episodes typically lasting for several hours, and none of them had muscle abnormalities including myokymia. Episodic ataxia type 1 (EA1) was not considered initially as a clinical diagnosis for the affected individuals in this family. However, by linkage mapping, sequencing and polymorphism analysis, all affecteds were found to have a novel mutation in KCNA1. Numerous missense mutations have been described previously in KCNA1 that cause EA1. The mutation c.1025G>T replaces a highly conserved serine with isoleucine at position 342 (p.Ser342Ile) in the highly conserved fifth transmembrane domain of the KCNA1. This mutation leads to a distinct clinical phenotype without myokymia broadening the scope of clinical characteristics of EA1 and highlighting the heterogeneity of phenotypic effects from distinct missense mutations.

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“…Historically, EEG has been applied in the differential diagnosis of "acetazolamide-responsive periodic ataxia" from epilepsy before a genetic allocation was possible [56]. After the identification of CACNA1A mutations, a growing body of literature focused on the co-occurrence of epileptic disorders in FHM1 and EA2 patients.…”

Section: Discussionmentioning

confidence: 99%

The electrophysiological footprint of CACNA1A disorders

et al. 2021

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Objectives CACNA1A variants underlie three neurological disorders: familial hemiplegic migraine type 1 (FHM1), episodic ataxia type 2 (EA2) and spinocerebellar ataxia type 6 (SCA6). EEG is applied to study their episodic manifestations, but findings in the intervals did not gain attention up to date. Methods We analyzed repeated EEG recordings performed between 1994 and 2019 in a large cohort of genetically confirmed CACNA1A patients. EEG findings were compared with those of CACNA1A-negative phenocopies. A review of the related literature was performed. Results 85 EEG recordings from 38 patients (19 EA2, 14 FHM1, 5 SCA6) were analyzed. Baseline EEG was abnormal in 55% of cases (12 EA2, 9 FHM1). The most common finding was a lateralized intermittent slowing, mainly affecting the temporal region. Slowing was more pronounced after a recent attack but was consistently detected in the majority of patients also during the follow-up. Interictal epileptic discharges (IEDs) were detected in eight patients (7 EA2,1 FHM1). EEG abnormalities and especially IEDs were significantly associated with younger age at examination (16 ± 9 vs 43 ± 21 years in those without epileptic changes, p = 0.003) and with earlier onset of disease (1 (1–2) vs 12 (5–45) years, p = 0.0009). EEG findings in CACNA1A-negative phenocopies (n = 15) were largely unremarkable (p = 0.03 in the comparison with CACNA1A patients). Conclusions EEG abnormalities between attacks are highly prevalent in episodic CACNA1A disorders and especially associated with younger age at examination and earlier disease onset. Our findings underpin an age-dependent effect of CACNA1A variants, with a more severe impairment when P/Q channel dysfunction manifests early in life.

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The electroencephalogram in acetazolamide‐responsive periodic ataxia

Cited by 17 publications

References 27 publications

The Role of Calcium Channels in Epilepsy

The Role of Calcium Channels in Epilepsy

A novel mutation in KCNA1 causes episodic ataxia without myokymia

The electrophysiological footprint of CACNA1A disorders

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