Bi-allelic SNAPC4 variants dysregulate global alternative splicing and lead to neuroregression and progressive spastic paraparesis.

The vast majority of human genes encode multiple isoforms through alternative splicing, and the temporal and spatial regulation of those isoforms is critical for organismal development and function. The spliceosome, which regulates and executes splicing reactions, is primarily composed of small nuclear ribonucleoproteins (snRNPs) that consist of small nuclear RNAs (snRNAs) and protein subunits. snRNA gene transcription is initiated by the snRNA-activating protein complex (SNAPc). Here, we report ten individuals, from eight families, with bi-allelic, deleterious SNAPC4 variants. SNAPC4 encoded one of the five SNAPc subunits that is critical for DNA binding. Most affected individuals presented with delayed motor development and developmental regression after the first year of life, followed by progressive spasticity that led to gait alterations, paraparesis, and oromotor dysfunction. Most individuals had cerebral, cerebellar, or basal ganglia volume loss by brain MRI. In the available cells from affected individuals, SNAPC4 abundance was decreased compared to unaffected controls, suggesting that the bi-allelic variants affect SNAPC4 accumulation. The depletion of SNAPC4 levels in HeLa cell lines via genomic editing led to decreased snRNA expression and global dysregulation of alternative splicing. Analysis of available fibroblasts from affected individuals showed decreased snRNA expression and global dysregulation of alternative splicing compared to unaffected cells. Altogether, these data suggest that these bi-allelic SNAPC4 variants result in loss of function and underlie the neuroregression and progressive spasticity in these affected individuals.

Safety and efficacy of avalglucosidase alfa in individuals with infantile-onset Pompe disease enrolled in the phase 2, open-label Mini-COMET study: The 6-month primary analysis report.

PURPOSE: Mini-COMET (NCT03019406; Sanofi) is a phase 2, open-label, ascending-dose, 3-cohort study, evaluating avalglucosidase alfa safety, pharmacokinetics, and efficacy in individuals with infantile-onset Pompe disease aged <18 years who previously received alglucosidase alfa and showed clinical decline (cohorts 1 and 2) or suboptimal response (cohort 3). METHODS: During a 25-week primary analysis period, cohorts 1 and 2 received avalglucosidase alfa 20 and 40 mg/kg every other week, respectively, for 6 months, whereas cohort 3 individuals were randomized (1:1) to receive avalglucosidase alfa 40 mg/kg every other week or alglucosidase alfa (current stable dose) for 6 months. RESULTS: In total, 22 individuals were enrolled (cohort 1 [n = 6], cohort 2 [n = 5], cohort 3-avalglucosidase alfa [n = 5], and cohort 3-alglucosidase alfa [n = 6]). Median treatment compliance was 100%. None of the individuals discontinued treatment or died. Percentages of individuals with treatment-emergent adverse events were similar across dose and treatment groups. No serious or severe treatment-related treatment-emergent adverse events occurred. Trends for better motor function from baseline to week 25 were observed for 40 mg/kg every other week avalglucosidase alfa compared with either 20 mg/kg every other week avalglucosidase alfa or alglucosidase alfa up to 40 mg/kg weekly. CONCLUSION: These data support the positive clinical effect of avalglucosidase alfa in patients with infantile-onset Pompe disease previously declining on alglucosidase alfa.

Loss-of-function mutations in SGCE found in Japanese patients with myoclonus-dystonia.

SGCE myoclonus-dystonia is a monogenic form of dystonia with an autosomal dominant mode of inheritance that co-occurs with a myoclonic jerk. In this study, we present 12 Japanese patients from nine families with this disease. Targeted next-generation sequencing covering major causative genes for monogenic dystonias identified nine distinct SGCE mutations from each of the families: three nonsense, two frameshift, two missense, one in-frame 15 bp deletion, and one splice donor site mutations, of which four were previously unreported. One missense mutation (c.662G>T, p.Gly221Val) was located at the 3' end of exon 5 (NM_001099400), which was predicted to cause aberrant splicing according to in silico predictions. Minigene assays performed together with the c.825+1G>C mutation demonstrated complete skipping of exon 5 and 6, respectively, in their transcripts. The other missense (c.1345A>G, p.Met449Val) and 15 bp deletion (c.168_182del, p.Phe58_Leu62del) mutations showed a significant reduction in cell membrane expression via HiBiT bioluminescence assay. Therefore, we concluded that all the detected mutations were disease-causing. Unlike the other detected mutations, p.Met449Val affects only isoform 3 (NP_001092870 encoded by NM_001099400) among the variously known isoforms of SGCE. This isoform is brain-specific and is mostly expressed in the cerebellum, which supports recent studies showing that cerebellar dysfunction is a key element in the pathophysiology of SGCE myoclonus-dystonia.

An intronic GNAO1 variant leading to in-frame insertion cause movement disorder controlled by deep brain stimulation.

GNAO1 variants are associated with a wide range of neurodevelopmental disorders including epileptic encephalopathies and movement disorders. It has been reported that some GNAO1 variants are associated with movement disorders, and the 207-246 amino acid region was proposed as a mutational hotspot. Here, we report an intronic variant (NM_020988.3:c.724-8G>A) in GNAO1 in a Japanese girl who showed mild developmental delay and movement disorders including dystonia and myoclonus. Her movement disorders were improved by deep brain stimulation treatment as previously reported. This variant has been recurrently reported in four patients and was transmitted from her mother who possessed the variant as low-prevalent mosaicism. Using RNA extracted from lymphoblastoid cells derived from the patient, we demonstrated that the variant caused abnormal splicing of in-frame 6-bp intronic retention, leading to 2 amino acid insertion (p.Thr241_Asn242insProGln). Immunoblotting and immunostaining using WT and mutant GNAO1 vectors showed no significant differences in protein expression levels, but the cellular localization pattern of this mutant was partially shifted to the cytoplasm whereas WT was exclusively localized in the cellular membrane. Our report first clarified abnormal splicing and resulting mutant protein caused by the c.724-8G>A variant.

Genetic and clinical landscape of childhood cerebellar hypoplasia and atrophy.

PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.

Pathogenic MAST3 Variants in the STK Domain Are Associated with Epilepsy.

OBJECTIVE: The MAST family of microtubule-associated serine-threonine kinases (STKs) have distinct expression patterns in the developing and mature human and mouse brain. To date, only MAST1 has been conclusively associated with neurological disease, with de novo variants in individuals with a neurodevelopmental disorder, including a mega corpus callosum. METHODS: Using exome sequencing, we identify MAST3 missense variants in individuals with epilepsy. We also assess the effect of these variants on the ability of MAST3 to phosphorylate the target gene product ARPP-16 in HEK293T cells. RESULTS: We identify de novo missense variants in the STK domain in 11 individuals, including 2 recurrent variants p.G510S (n = 5) and p.G515S (n = 3). All 11 individuals had developmental and epileptic encephalopathy, with 8 having normal development prior to seizure onset at <2 years of age. All patients developed multiple seizure types, 9 of 11 patients had seizures triggered by fever and 9 of 11 patients had drug-resistant seizures. In vitro analysis of HEK293T cells transfected with MAST3 cDNA carrying a subset of these patient-specific missense variants demonstrated variable but generally lower expression, with concomitant increased phosphorylation of the MAST3 target, ARPP-16, compared to wild-type. These findings suggest the patient-specific variants may confer MAST3 gain-of-function. Moreover, single-nuclei RNA sequencing and immunohistochemistry shows that MAST3 expression is restricted to excitatory neurons in the cortex late in prenatal development and postnatally. INTERPRETATION: In summary, we describe MAST3 as a novel epilepsy-associated gene with a potential gain-of-function pathogenic mechanism that may be primarily restricted to excitatory neurons in the cortex. ANN NEUROL 2021;90:274-284.

Prenatal clinical manifestations in individuals with COL4A1/2 variants.

BACKGROUND: Variants in the type IV collagen gene (COL4A1/2) cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with COL4A1/2 variants remain unclear. METHODS: We examined COL4A1/2 in 218 individuals with suspected COL4A1/2-related brain defects. Among those arising from COL4A1/2 variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail. RESULTS: Pathogenic COL4A1/2 variants were detected in 56 individuals (n=56/218, 25.7%) showing porencephaly (n=29), schizencephaly (n=12) and others (n=15). Thirty-four variants occurred de novo (n=34/56, 60.7%). Foetal information was available in 47 of 56 individuals, 32 of whom (n=32/47, 68.1%) had one or more foetal abnormalities. The median gestational age at the detection of initial prenatal abnormal features was 31 weeks of gestation. Only 14 individuals had specific prenatal findings that were strongly suggestive of features associated with COL4A1/2 variants. Foetal ventriculomegaly was the most common initial feature (n=20/32, 62.5%). Posterior fossa abnormalities, including Dandy-Walker malformation, were observed prenatally in four individuals. Regarding extrabrain features, foetal growth restriction was present in 16 individuals, including eight individuals with comorbid ventriculomegaly. CONCLUSIONS: Prenatal observation of ventriculomegaly with comorbid foetal growth restriction should prompt a thorough ultrasound examination and COL4A1/2 gene testing should be considered when pathogenic variants are strongly suspected.

De Novo Variants in the F-Box Protein FBXO11 in 20 Individuals with a Variable Neurodevelopmental Disorder.

Next-generation sequencing combined with international data sharing has enormously facilitated identification of new disease-associated genes and mutations. This is particularly true for genetically extremely heterogeneous entities such as neurodevelopmental disorders (NDDs). Through exome sequencing and world-wide collaborations, we identified and assembled 20 individuals with de novo variants in FBXO11. They present with mild to severe developmental delay associated with a range of features including short (4/20) or tall (2/20) stature, obesity (5/20), microcephaly (4/19) or macrocephaly (2/19), behavioral problems (17/20), seizures (5/20), cleft lip or palate or bifid uvula (3/20), and minor skeletal anomalies. FBXO11 encodes a member of the F-Box protein family, constituting a subunit of an E3-ubiquitin ligase complex. This complex is involved in ubiquitination and proteasomal degradation and thus in controlling critical biological processes by regulating protein turnover. The identified de novo aberrations comprise two large deletions, ten likely gene disrupting variants, and eight missense variants distributed throughout FBXO11. Structural modeling for missense variants located in the CASH or the Zinc-finger UBR domains suggests destabilization of the protein. This, in combination with the observed spectrum and localization of identified variants and the lack of apparent genotype-phenotype correlations, is compatible with loss of function or haploinsufficiency as an underlying mechanism. We implicate de novo missense and likely gene disrupting variants in FBXO11 in a neurodevelopmental disorder with variable intellectual disability and various other features.

Identification of two novel de novo TUBB variants in cases with brain malformations: case reports and literature review.

Heterozygous variants in TUBB encoding one of ß-tubulin isotypes are known to cause two overlapping developmental brain disorders, complex cortical dysplasia with other brain malformations (CDCBM) and congenital symmetric circumferential skin creases (CSCSC). To date, six cases of CSCSC and eight cases of CDCBM caused by nine heterozygous variants have been reported. Here we report two cases with novel de novo missense TUBB variants (NM_178014.4:c.863A>G, p.(Glu288Gly) and c.869C>T, p.(Thr290Ile)). Case 1 presented brain malformations consistent with tubulinopathies including abnormalities in cortex, basal ganglia, corpus callosum, brain stem, and cerebellum along with other systemic features such as coloboma, facial dysmorphisms, vesicoureteral reflux, hypoplastic kidney, and cutis laxa-like mild skin loosening. Another case presented abnormalities of the corpus callosum, brain stem, and cerebellum along with facial dysmorphisms. We reviewed previous literature and suggest the diversity of clinical findings of TUBB-related disorders.

Novel EXOSC9 variants cause pontocerebellar hypoplasia type 1D with spinal motor neuronopathy and cerebellar atrophy.

Pontocerebellar hypoplasia (PCH) is currently classified into 13 subgroups and many gene variants associated with PCH have been identified by next generation sequencing. PCH type 1 is a rare heterogeneous neurodegenerative disorder. The clinical presentation includes early-onset severe developmental delay, progressive motor neuronopathy, and cerebellar and pontine atrophy. Recently two variants in the EXOSC9 gene (MIM: 606180), NM_001034194.1: c.41T>C (p.Leu14Pro) and c.481C>T (p.Arg161*) were identified in four unrelated patients with PCH type 1D (PCH1D) (MIM: 618065). EXOSC9 encodes a component of the exosome complex, which is essential for correct processing and degradation of RNA. We report here two PCH1D families with biallelic EXOSC9 variants: c.239T>G (p.Leu80Arg) and c.484dupA (p.Arg162Lysfs*3) in one family and c.151G>C (p.Gly51Arg) in the other family. Although the patients studied here showed similar clinical features as previously described for PCH1D, relatively greater intellectual development (although still highly restricted) and normal pontine structure were recognized. Our findings expand the clinical consequences of biallelic EXOSC9 variants.

Genetic landscape of Rett syndrome-like phenotypes revealed by whole exome sequencing.

BACKGROUND: Rett syndrome (RTT) is a characteristic neurological disease presenting with regressive loss of neurodevelopmental milestones. Typical RTT is generally caused by abnormality of methyl-CpG binding protein 2 (MECP2). Our objective to investigate the genetic landscape of MECP2-negative typical/atypical RTT and RTT-like phenotypes using whole exome sequencing (WES). METHODS: We performed WES on 77 MECP2-negative patients either with typical RTT (n=11), atypical RTT (n=22) or RTT-like phenotypes (n=44) incompatible with the RTT criteria. RESULTS: Pathogenic or likely pathogenic single-nucleotide variants in 28 known genes were found in 39 of 77 (50.6%) patients. WES-based CNV analysis revealed pathogenic deletions involving six known genes (including MECP2) in 8 of 77 (10.4%) patients. Overall, diagnostic yield was 47 of 77 (61.0 %). Furthermore, strong candidate variants were found in four novel genes: a de novo variant in each of ATPase H+ transporting V0 subunit A1 (ATP6V0A1), ubiquitin-specific peptidase 8 (USP8) and microtubule-associated serine/threonine kinase 3 (MAST3), as well as biallelic variants in nuclear receptor corepressor 2 (NCOR2). CONCLUSIONS: Our study provides a new landscape including additional genetic variants contributing to RTT-like phenotypes, highlighting the importance of comprehensive genetic analysis.

De novo hotspot variants in CYFIP2 cause early-onset epileptic encephalopathy.

OBJECTIVE: The cytoplasmic fragile X mental retardation 1 interacting proteins 2 (CYFIP2) is a component of the WASP-family verprolin-homologous protein (WAVE) regulatory complex, which is involved in actin dynamics. An obvious association of CYFIP2 variants with human neurological disorders has never been reported. Here, we identified de novo hotspot CYFIP2 variants in neurodevelopmental disorders and explore the possible involvement of the CYFIP2 mutants in the WAVE signaling pathway. METHODS: We performed trio-based whole-exome sequencing (WES) in 210 families and case-only WES in 489 individuals with epileptic encephalopathies. The functional effect of CYFIP2 variants on WAVE signaling was evaluated by computational structural analysis and in vitro transfection experiments. RESULTS: We identified three de novo CYFIP2 variants at the Arg87 residue in 4 unrelated individuals with early-onset epileptic encephalopathy. Structural analysis indicated that the Arg87 residue is buried at an interface between CYFIP2 and WAVE1, and the Arg87 variant may disrupt hydrogen bonding, leading to structural instability and aberrant activation of the WAVE regulatory complex. All mutant CYFIP2 showed comparatively weaker interactions to the VCA domain than wild-type CYFIP2. Immunofluorescence revealed that ectopic speckled accumulation of actin and CYFIP2 was significantly increased in cells transfected with mutant CYFIP2. INTERPRETATION: Our findings suggest that de novo Arg87 variants in CYFIP2 have gain-of-function effects on the WAVE signaling pathway and are associated with severe neurological disorders. Ann Neurol 2018;83:794-806.

Identification of novel SNORD118 mutations in seven patients with leukoencephalopathy with brain calcifications and cysts.

BACKGROUND: Leukoencephalopathy with brain calcifications and cysts (LCC) is neuroradiologically characterized by leukoencephalopathy, intracranial calcification, and cysts. Coats plus syndrome is also characterized by the same neuroradiological findings together with defects in retinal vascular development. Indeed, LCC and Coats plus were originally considered to be the same clinical entity termed cerebroretinal microangiopathy with calcifications and cysts, but evidence suggests that they are genetically distinct. Mutations in CTS telomere maintenance complex component 1 (CTC1) and small nucleolar RNA, C/D box 118 (SNORD118) genes have been found to cause Coats plus and LCC, respectively. MATERIALS AND METHODS: Eight unrelated families with LCC were recruited. These patients typically showed major neuroradiological findings of LCC with no signs of extra-neurological manifestations such as retinal abnormality, gastrointestinal bleeding, or hematological abnormalities. SNORD118 was examined by Sanger sequencing in these families. RESULTS: Seven out of eight probands carry compound heterozygous mutations, suggesting that SNORD118 mutations are the major cause of LCC. We identified a total of eight mutation, including four that were novel. Some of the variants identified in this study present heterozygously in public databases with an extremely rare frequency (<0.1%). CONCLUSION: Biallelic SNORD118 mutations were exclusively found in most unrelated families with LCC.

Vagus Nerve Stimulation Therapy for Drug-Resistant Epilepsy in Children-A Literature Review.

Vagus nerve stimulation (VNS) is a palliative treatment for drug-resistant epilepsy (DRE) that has been in use for over two decades. VNS suppresses epileptic seizures, prevents emotional disorders, and improves cognitive function and sleep quality, a parallel effect associated with the control of epileptic seizures. The seizure suppression rate with VNS increases monthly to annually, and the incidence of side effects reduces over time. This method is effective in treating DRE in children as well as adults, such as epilepsy associated with tuberous sclerosis, Dravet syndrome, and Lennox-Gastaut syndrome. In children, it has been reported that seizures decreased by >70% approximately 8 years after initiating VNS, and the 50% responder rate was reported to be approximately 70%. VNS regulates stimulation and has multiple useful systems, including self-seizure suppression using magnets, additional stimulation using an automatic seizure detection system, different stimulation settings for day and night, and an automatic stimulation adjustment system that reduces hospital visits. VNS suppresses seizures and has beneficial behavioral effects in children with DRE. This review describes the VNS system, the mechanism of the therapeutic effect, the specific stimulation adjustment method, antiepileptic effects, and other clinical effects in patients with childhood DRE.

Pallidal deep brain stimulation for patients with myoclonus-dystonia without SGCE mutations.

BACKGROUND: Pallidal deep brain stimulation (GPi-DBS) is effective for treating myoclonus and dystonia caused by SGCE mutations (DYT-SGCE, DYT11). However, it is unknown whether GPi-DBS is effective for the treatment of myoclonus-dystonia which is not associated with the SGCE gene mutations. In this study, we investigated the efficacy of GPi-DBS in treating myoclonus-dystonia in SGCE mutation-negative cases. METHODS: Three patients with myoclonus-dystonia without SGCE mutations who underwent GPi-DBS were evaluated preoperatively and 6 months postoperatively using the Unified Myoclonus Rating Scale (UMRS) and Fahn-Marsden Dystonia Rating Scale (FMDRS) for myoclonus and dystonia, respectively. In two of the three patients, myoclonus was more evident during action. Myoclonus was predominant at rest in the other patient, and he was unaware of his dystonia symptoms. The results were compared with those of the four DYT-SGCE cases. RESULTS: The mean UMRS score in patients with myoclonus-dystonia without SGCE mutations improved from 61.7 to 33.7 pre- and postoperatively, respectively, and the mean FMDRS score improved from 7.2 to 4.5. However, the degree of improvement in myoclonus-dystonia in patients without SGCE mutations was inferior to that in patients with DYT-SGCE (the UMRS score improved by 45% and 69%, respectively). CONCLUSIONS: GPi-DBS is effective for treating myoclonus-dystonia in patients with and without SGCE mutations. GPi-DBS should be considered as a treatment option for myoclonus-dystonia without SGCE mutations.

[Issues of transition support to adulthood and the practices of pediatric-adult healthcare transition in neurological diseases].

A workshop of the Special Committee on Measures for Transition from Pediatric to Adult Health Care, the Japanese Society of Neurology was held to discuss various issues and practices involved in healthcare transition. The following points were addressed: (1) the history of, and issues involved in, promoting support for patients requiring medical care, (2) cooperation between pediatric medical centers and university hospitals, (3) collaboration between pediatrics and neurology in medical and rehabilitation facilities, and (4) a questionnaire survey of members of the Japanese Society of Neurology. The reasons for extreme difficulties in pediatric-adult healthcare transition for patients with neurological diseases, especially those who require continuous intensive medical care over a long period of time, include the difference in the operating systems of pediatric and adult departments, in addition to the difference in the diseases treated during childhood and adulthood. For holistic transition support, it is necessary to strengthen cooperation not only among medical professionals, but also among multiple professions, as well as between local communities and government.

Reduced histone H3K4 trimethylation in oral mucosa of patients with DYT-KMT2B.

BACKGROUND: DYT-KMT2B, also known as DYT28, is a childhood-onset hereditary dystonia caused by KMT2B mutation. The pathogenesis of DYT-KMT2B involves haploinsufficiency of KMT2B, an enzyme that catalyzes specific histone methylation (H3K4me3). Dysmorphic features in patients with DYT-KMT2B suggest that KMT2B dysfunction may extend beyond the neuronal system. Therefore, valuable diagnostic insights may be obtained from readily available tissue samples. OBJECTIVES: To explore the altered H3K4me3 levels in non-neural tissue of DYT-KMT2B patients. METHODS: A database analysis was performed to determine in which parts of the body and in which cells KMT2B is highly expressed. Twelve clinically and genetically diagnosed patients with DYT-KMT2B and 12 control subjects participated in this study. Oral mucosa-derived purified histone proteins were analyzed using Western blotting with anti-H3K4me3 and anti-H4 antibodies. RESULTS: Higher expression of KMT2B was observed in oral keratinocytes and gingival fibroblasts, constituting the oral mucosa. In oral mucosa analyses, DYT-KMT2B cases exhibited markedly reduced H3K4me3 levels compared with the controls. Using a cutoff window of 0.90-0.98, the H3K4me3/H4 expression ratio was able to distinguish patient groups. CONCLUSIONS: Oral mucosa H3K4me3 analysis is currently not sufficient as a diagnostic tool for DYT-KMT2B, but has the advantage for screening test since it is a non-invasive means.

[Current practices of transition from pediatric to adult health care for patients with neurological disease: promote the cooperation between child and adult neurologists].

The Special Committee for Measures Against Transition from Pediatric to Adult Health Care of the Japanese Society of Neurology, which consists of child and adult neurologists, started to tackle the issues of pediatric to adult health care transition for patients with neurological disease in July 2020. The Committee held a workshop with a theme of "cooperation between child and adult neurologists," which is a critical issue in the pediatric to adult health care transition. To solve the many problems in the pediatric to adult health care transition, it is crucial that child and adult neurologists and primary care physicians cooperate on the following issues: preparing child neurologists for the transition, encouraging adult neurologists to study child neurology, promoting the formation of multidisciplinary teams, improving the medical system and medical fees, appealing to governmental agencies for issues of community health care and welfare services.

Focal tonic seizures with asymmetrical posturing could allow voluntary movements: A lesson to not be misled for a non-epileptic event.

This report documents the clinical features of supplementary motor area seizures with voluntary movements in two patients. The first case describes a 13-year-old boy with a 2-year history of nocturnal seizures, characterized by an asymmetrical brief tonic posture followed by bilateral rapid hand shaking, but without impaired awareness. Magnetic resonance imaging revealed no abnormalities. Video electroencephalogram indicated interictal focal spikes and ictal activity 2 s before clinical onset in the frontal midline area. The patient stated that he purposely shook his hands to lessen the seizure-induced upper limb stiffness. The second case describes a 43-year-old man with a 33-year history of nocturnal seizures, characterized by an asymmetric brief tonic posture, with the right hand grabbing to hold this posture, but without impaired awareness. Video electroencephalogram indicated that he voluntarily moved his right hand during the latter part of the seizures; however, no clear ictal electroencephalogram change was noted. Magnetic resonance imaging revealed a mass lesion in the right medial superior frontal gyrus. Fluorodeoxyglucose-positron emission tomography and ictal single-photon emission computed tomography indicated ictal focus in the mesial frontal area, as confirmed by invasive electroencephalogram and seizure freedom after surgery. Both patients had typical supplementary motor area seizures, except they could perform voluntary movements in the body parts. The co-occurrence of supplementary motor area seizures and voluntary movements is clinically useful, as it may help avoid the inaccurate and misleading diagnosis of non-epileptic events such as psychogenic non-epileptic seizures.