{"title":"Clinical characteristics for early diagnosis of PACS1 neurodevelopmental disorder: Two case reports","authors":"Ryo Takeguchi , Yoshio Makita , Shunsuke Haga , Ikue Fukuda , Akie Miyamoto , Hajime Tanaka , Taiga Aoki , Takaya Iida , Kumiko Yanagi , Tadashi Kaname , Satoru Takahashi","doi":"10.1016/j.bdcasr.2025.100111","DOIUrl":"10.1016/j.bdcasr.2025.100111","url":null,"abstract":"<div><h3>Background</h3><div><em>PACS1</em> neurodevelopmental disorder (<em>PACS1</em>-NDD), also known as Schuurs-Hoeijmakers syndrome, is a rare autosomal dominant disorder predominantly caused by the recurrent de novo pathogenic <em>PACS1</em> variant c.607C>T (p.Arg203Trp). The characteristic features include varying degrees of global developmental delay, autism spectrum disorder (ASD), behavioral problems, and distinct facial features. Although the number of reported cases has increased, <em>PACS1</em>-NDD remains underrecognized, suggesting that many cases remain undiagnosed.</div></div><div><h3>Case presentation</h3><div>We report two Japanese pediatric patients diagnosed with <em>PACS1</em>-NDD using whole-exome sequencing (WES) and filtering analysis to identify the recurrent pathogenic variant [NM_018026.4:c.607C>T,p.(Arg203Trp)]. Patient 1, a 4-year-old boy, demonstrated severe global developmental delay, ASD, behavioral problems, sleep disturbances, epilepsy, cryptorchidism, and chronic constipation. Patient 2, a 3-year-old girl, demonstrated profound global developmental delay, ASD, behavioral problems, sleep disturbances, mild cerebral atrophy, congenital heart defects, and chronic constipation. Both patients shared consistent facial features, including hypertelorism, downslanted palpebral fissures, a short nose with anteverted nares, a thin upper lip, and downturned mouth corners.</div></div><div><h3>Discussion</h3><div>This study provides critical diagnostic clues for <em>PACS1</em>-NDD to facilitate early recognition based on a combination of characteristic facial features, global developmental delays, ASD, and sleep disturbances. In addition, other systemic complications such as cryptorchidism, congenital heart defects, and chronic constipation have been frequently reported in <em>PACS1</em>-NDD. Recognizing these clinical features can strengthen the clinical indication for comprehensive genetic testing, such as WES. Early diagnosis enables tailored clinical management and genetic counseling for patients and their families.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100111"},"PeriodicalIF":0.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Acute cerebellitis in a 10-year-old male: Diagnostic and management challenges in a resource-limited setting","authors":"Erneus Ernest , Adam Chai","doi":"10.1016/j.bdcasr.2025.100112","DOIUrl":"10.1016/j.bdcasr.2025.100112","url":null,"abstract":"<div><h3>Introduction</h3><div>Acute cerebellitis (AC) is an inflammatory disease of the cerebellum following viral, bacterial infections, or autoimmune-mediated processes. Diagnosis and management of its complications, such as hydrocephalus, are particularly challenging in resource-limited settings. This report highlights these challenges and the successful outcome achieved with conservative medical management, averting the need for surgical intervention for AC-associated obstructive hydrocephalus.</div></div><div><h3>Case presentation</h3><div>A 10-year-old male was referred to our facility with a complaint of persistent headache for 10 days associated with cerebellar signs (wide-based gait, dysarthria, and dysmetria) and projectile vomiting. Brain MRI showed features of AC with moderate hydrocephalus. The patient was managed conservatively with intravenous ceftriaxone, dexamethasone, and acetazolamide. This led to complete clinical recovery and averted the need for surgical intervention. A follow-up MRI one-month post-treatment confirmed complete radiological resolution of both the cerebellitis and hydrocephalus.</div></div><div><h3>Conclusion</h3><div>This case underscores the importance of a high index of suspicion for AC in resource-limited settings when a child presents with headache and neurological signs. It demonstrates that medical management with steroids and acetazolamide can successfully resolve AC-associated obstructive hydrocephalus in select patients. This approach offers a viable strategy to avoid neurosurgical intervention in environments where resources are constrained.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100112"},"PeriodicalIF":0.0,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145266602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Neuronal ceroid lipofuscinosis type 2 disease in a 4-year-old child with epilepsy and concerns for stuttering","authors":"Lorena Galvan , Dorota Szczepaniak , Bri Dingmann , Emily Myers","doi":"10.1016/j.bdcasr.2025.100110","DOIUrl":"10.1016/j.bdcasr.2025.100110","url":null,"abstract":"<div><h3>Background</h3><div>Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a rare neurodegenerative neuronal lysosomal storage disease associated with ataxia, seizures, vision loss, and clinical deterioration. Early diagnosis is of crucial importance to initiate early treatment with intraventricular enzyme replacement therapy. Though seizures are typically the first presenting symptom associated with CLN2, recent research suggests that language and speech delays may precede seizures.</div></div><div><h3>Case presentation</h3><div>Our case is a 4-year-old child with epilepsy who presented to our neurodevelopmental clinic with stuttering. Prior to his epilepsy diagnosis at approximately 41 months of age, the child demonstrated delayed early language milestones during infancy. Genetic and enzymatic testing confirmed the diagnosis of CLN2. We discuss his overall clinical presentation and current research regarding speech and language delays in CLN2.</div></div><div><h3>Conclusion</h3><div>There is emerging evidence that stuttering may be one of the early speech and language characterizations of children with CLN2. Our case supports this emerging evidence and may direct clinicians to recognize speech production differences as an early presentation of CLN2.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100110"},"PeriodicalIF":0.0,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Delayed identification of MYBPC1-related myopathy in adolescence: Diagnostic value of resting tongue ultrasonography in myogenic tremor","authors":"Megumi Tsuji , Yukiko Kuroda , Shotaro Morikawa , Yutaka Hatano , Azusa Ikeda , Tomohide Goto","doi":"10.1016/j.bdcasr.2025.100109","DOIUrl":"10.1016/j.bdcasr.2025.100109","url":null,"abstract":"<div><h3>Background</h3><div>The <em>MYBPC1</em> gene, which encodes the slow skeletal myosin binding protein-C, has recently been identified as the causative gene for a rare, mild myopathy associated with myogenic tremor</div></div><div><h3>Case presentation</h3><div>Our patient was a Japanese girl born full-term via normal delivery. No consanguinity or family history of neuromuscular disorders was reported. The patient's motor developmental milestones were slightly delayed. Independent walking was not achieved until 1 year and 7 months of age. Hand tremors had been observed since 2 years of age. The patient was not physically active and had been experiencing fatigue since 12 years of age. At her first visit to our hospital at 14 years of age, she presented with distal muscle weakness, a high-arched palate, decreased deep tendon reflexes, involuntary tongue movement resembling fasciculations, and mild scoliosis. However, the patient's nerve conduction velocity and electromyogram results were normal. Ultrasonographic examination of the tongue revealed rhythmic movement, consistent with tremors, which disappeared at rest. A heterozygous, missense pathogenic variant (c.[788T>G] (p.Leu263Arg)) in the <em>MYBPC1</em> gene was identified using the TruSight One Sequencing Panel</div></div><div><h3>Discussion</h3><div>Muscle weakness is caused by the altered binding of the mutant MYBPC1 protein to myosin. However, the mechanism by which the dysfunction of the MYBPC1 protein, which is not expressed in the central or peripheral nervous system, leads to tremors remains unclear. The diagnosis can only be confirmed via genetic testing. However, tongue tremors may be mistaken for fasciculations. Electromyography and tongue ultrasonography may be useful in achieving an early diagnosis.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100109"},"PeriodicalIF":0.0,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145060500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamics of the cytokine profiles in Rasmussen's encephalitis: A case report","authors":"Kotaro Watanabe, Kengo Moriyama, Shuya Kaneko, Asami Shimbo, Taisuke Yamauchi, Yumie Tamura, Hitoshi Irabu, Masaki Shimizu, Masatoshi Takagi, Tomoko Mizuno","doi":"10.1016/j.bdcasr.2025.100107","DOIUrl":"10.1016/j.bdcasr.2025.100107","url":null,"abstract":"<div><h3>Introduction</h3><div>Although cytotoxic T cells (CTL) and activated microglia affect the pathophysiology of Rasmussen's encephalitis (RE), the correlation between these immune cells and cytokines has yet to be elucidated. We analyzed the dynamics of the cytokine profiles in a patient with RE.</div></div><div><h3>Case presentation</h3><div>A 6-year-old girl without any medical history developed right hemiconvulsions. EEG showed left parietal to temporal epileptiform discharges, and positron emission tomography revealed left parietal lobe hypoperfusion. At age 9 years, the patient developed epilepsia partialis continua, with subsequent MRI showing mild atrophy of the left hemisphere, based on which a diagnosis of RE was established. Monthly methylprednisolone pulse therapy was then initiated, with the patient's cytokine profiles being recorded at four time points. In the acute phase, C-X-C motif chemokine 9 (CXCL9) increased but later decreased in the cerebrospinal fluid (CSF). Meanwhile, interleukin-6 (IL-6) was negative in the acute phase but increased in the chronic phase.</div></div><div><h3>Discussion</h3><div>Elevated CXCL9 in the CSF during the acute phase indicates increased secretion of interferon γ due to the abnormal activation of CTL, which is characteristic of RE. Hence, measuring CXCL9 levels in the CSF during the acute phase may help diagnose RE. We observed elevated IL-6 levels in the CSF during the chronic phase, which possibly reflects long-lasting central nervous system inflammation.</div></div><div><h3>Conclusion</h3><div>We outline the cytokine profile dynamics in an RE patient in hopes of contributing to the early diagnosis of RE and selection of therapeutic approach.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100107"},"PeriodicalIF":0.0,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Severe pediatric case of longitudinally extensive transverse myelitis, brainstem encephalitis, and peripheral neuropathy with double positive anti-glial fibrillary acidic protein α and anti-lactosylceramide antibodies","authors":"Satoru Ikemoto , Tetsumaru Fujita , Haruka Takami , Ken Ito , Toshiki Tsunogai , Norimichi Higurashi , Satoshi Matsushima , Akio Kimura , Takayoshi Shimohata , Tatsuro Mutoh","doi":"10.1016/j.bdcasr.2025.100105","DOIUrl":"10.1016/j.bdcasr.2025.100105","url":null,"abstract":"<div><h3>Background</h3><div>We present a pediatric case of longitudinally extensive transverse myelitis, brainstem encephalitis, and peripheral neuropathy, double positive for anti-glial fibrillary acidic protein (GFAP)α and anti-lactosylceramide (LacCer) antibodies, presenting GFAP-astrocytopathy (GFAP-A) and encephalo-myelo-radiculo-neuropathy (EMRN).</div></div><div><h3>Case presentation</h3><div>A 12-year-old boy presented with headaches and fever for 10 days. Initial clinical evaluation revealed hyponatremia, urinary retention, and altered consciousness with confusion. Brain magnetic resonance imaging (MRI) demonstrated a hyperintense abnormality in the splenium of the corpus callosum on T2- and diffusion-weighted images, consistent with reversible splenial lesion syndrome. The patient progressively experienced decreased consciousness and brainstem dysfunction (hypoventilation and brainstem reflex loss), was admitted to the intensive care unit, and treated for severe cardiac dysfunction and acute respiratory distress. Methylprednisolone, immunoglobulin, and plasma exchange were intravenously administered. A second MRI scan on day 31 showed multiple long T2 lesions in the brainstem and its surface, basal ganglia, thalamus, claustrum, white matter, and cerebellum. Spinal MRI revealed a longitudinally extensive spinal cord lesion extending into the central gray matter and enhanced nerve roots. Neural conductivity examination revealed motor axonopathy and loss of F-waves. Anti-GFAPα antibodies in the cerebrospinal fluid (CSF) and anti-LacCer antibodies in the serum and CSF were present. Gradually, the patient recovered from cardiac dysfunction and regained respiration and brainstem reflexes. Severe lower-limb-dominant flaccid paralysis and bladder and bowel dysfunctions remained.</div></div><div><h3>Discussion/Conclusion</h3><div>This severe case of overlapping anti-GFAPα and anti-LacCer antibodies highlights the importance of careful autoantibody examination in cases with EMRN and/or GFAP-A.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100105"},"PeriodicalIF":0.0,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A child case presenting with diffuse dural thickening due to a coma after unsuccessful treatment for a first-episode neuromyelitis optica spectrum disorder","authors":"Hayato Nishibayashi, Osamu Kobayashi, Tomoki Maeda, Kenji Ihara","doi":"10.1016/j.bdcasr.2025.100106","DOIUrl":"10.1016/j.bdcasr.2025.100106","url":null,"abstract":"<div><h3>Introduction</h3><div>Fulminant demyelinating diseases, including neuromyelitis optica spectrum disorder (NMOSD), progress rapidly with severe outcomes. We report a pediatric case of NMOSD with diffuse brain edema and a poor neurological prognosis.</div></div><div><h3>Case presentation</h3><div>A 6-year-old boy received an influenza vaccination 12 days prior to onset, and subsequently developed fever, headache, decreased urination frequency, and constipation. He presented with seizures and a disturbance of consciousness accompanied by hyperthermia (> 41 °C). Physical examination revealed tachycardia, neck stiffness, and papilledema. Magnetic resonance imaging (MRI) revealed scattered white matter lesions on T2-weighted images (T2WI) and longitudinally extensive spinal cord lesions from C4 to Th9. A cerebrospinal fluid (CSF) examination revealed elevated pressure and pleocytosis. Despite performing methylprednisolone pulse therapy following the diagnosis of NMOSD, the patient developed distributive shock. Intensive care was introduced, but the patient developed severe brain edema, and his consciousness did not recover after the cessation of intensive care. On day 30, an EEG revealed a flat trace. On day 38, contrast-enhanced MRI revealed diffuse dural thickening. Serum anti-aquaporin-4 antibodies and anti-myelin oligodendrocyte glycoprotein antibodies were negative.<em>Discussion:</em> We speculate that the combination of hyperthermia, intracranial hypertension, and distributive shock led to severe cerebral ischemia in this case. Even in the absence of overt brain edema the initial MRI, a severe clinical course may still occur.</div></div><div><h3>Conclusion</h3><div>In cases of acute encephalopathy or encephalitis presenting with spinal cord symptoms, hyperthermia, and intracranial hypertension, aggressive temperature and circulatory management under intensive care is essential to prevent severe brain edema.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 4","pages":"Article 100106"},"PeriodicalIF":0.0,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144908869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Cytotoxic white matter lesions in Menkes disease: A case report of centrum semiovale involvement","authors":"Aki Kawakami , Mikako Enokizono , Sahoko Miyama","doi":"10.1016/j.bdcasr.2025.100103","DOIUrl":"10.1016/j.bdcasr.2025.100103","url":null,"abstract":"<div><h3>Background</h3><div>Menkes disease is a rare disorder of copper metabolism characteristically presenting kinky hair as well as neurological symptoms, including epilepsy, developmental delay, and hypotonia. While the kinky hair is a consistent and distinguishing feature, the other symptoms are nonspecific. Neuroimaging studies often find vascular tortuosity and cerebral atrophy whereas white matter involvement is less well-characterized. Most of the lesions stem from vasogenic edema, and reports of cytotoxic changes are rare.</div></div><div><h3>Case presentation</h3><div>We report herein a 10-month-old, male patient with Menkes disease who presented with developmental delay and epileptic spasms. Diffusion-weighted imaging (DWI) revealed symmetrical, oval-shaped areas of hyperintensity with a decreased apparent diffusion coefficient (ADC) in the bilateral centrum semiovale. Proton magnetic resonance spectroscopy (<sup>1</sup>H-MRS) demonstrated elevated lactate, suggesting an underlying mitochondrial dysfunction.</div></div><div><h3>Conclusion</h3><div>The findings of the present case indicated that Menkes disease can present not only vascular abnormalities but also cytotoxic white matter lesions in the centrum semiovale, thus highlighting the risk of metabolic injury in addition to that of ischemia.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 3","pages":"Article 100103"},"PeriodicalIF":0.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144866478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long-term natural course of spinal deformity in a patient with type 1 spinal muscular atrophy: A case report","authors":"Chikao Ohigashi , Masako Tsukanaka , Kenji Inoue","doi":"10.1016/j.bdcasr.2025.100104","DOIUrl":"10.1016/j.bdcasr.2025.100104","url":null,"abstract":"<div><h3>Background</h3><div>Spinal muscular atrophy (SMA) is a neuromuscular disease characterized by muscle atrophy and weakness. Patients with type 1 SMA become symptomatic within the first 6 months of their lives. As most patients die before the age of 2, spinal deformity has not been a clinical problem; however, with the emergence of disease-modified therapies (DMT), longer survival is expected. Nonetheless, little is known about the natural long-term course of spinal deformities in patients with type 1 SMA. <em>Case presentation</em>: We report a case of type 1 SMA treated with supportive care without DMT until the age of 22. Radiography revealed a bell-shaped chest at 9 months of age. Thoracic scoliosis was first observed at age 3, progressed to a Cobb angle of 68° at age 13, and remained stable until the age of 26 years. Computed tomography (CT) images obtained after skeletal maturity revealed thoracic lordosis and spontaneous fusion of the lumbar laminae.</div></div><div><h3>Discussion</h3><div>Respiratory failure is the leading cause of death with type 1 SMA, and chest wall deformities can result in reduced breathing capacity and tracheal obstruction. In this case, the slow progression of the deformities may have contributed to the stable ventilation. Thoracic lordosis was also observed. This finding contrasts with the previously reported thoracic kyphosis in patients with type 2 SMA. Three-dimensional computerised tomography (3DCT) images demonstrated laminar fusion, which contributed to spinal stability.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 3","pages":"Article 100104"},"PeriodicalIF":0.0,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144878227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Paroxysmal dyskinesia on awakening: A new familial form of non- kinesigenic dyskinesia","authors":"Natan Gadoth","doi":"10.1016/j.bdcasr.2025.100101","DOIUrl":"10.1016/j.bdcasr.2025.100101","url":null,"abstract":"<div><h3>Background</h3><div>The sleep-to-wake and wake –to –sleep transitions known also as post and pre- <em>dormitum</em> are short events resulting from fine activation and deactivation of brain-stem and forebrain modulatory systems. Although sleep related movement disorders (SRMD) were recognized as a new category of sleep disorders since the 2nd version of the International Classification of Sleep Disorders, (ICSD-2), the mentioned list of those disorders did not include movement disorders occurring just before falling asleep or on awakening. Moreover, in a review of sleep-to-wake transitional movement disorders, only propriospinal myoclonus was mention as occurring during awakening.</div></div><div><h3>Case presentation</h3><div>we describe a brother and sister with chronic short events of dyskinesia occurring exclusively on awakening from nocturnal as well as daytime sleep, without evidence of additional neurological or medical abnormalities. Both siblings showed a prompt response to low dose of clonazepam (clonex<sup>R</sup>), with long term and complete remission and without ill side effects. The clinical characteristics of this particular movement disorder are unique. A short video clip of the brother is included.</div></div><div><h3>Conclusion</h3><div>Our patients suffer from paroxysmal non-kinesigenic dyskinesia. The relation to sleep suggests that the disorder in our patients represents a new and unique form of familial paroxysmal hypnogenic dyskinesia responsive to clonazepam.</div></div>","PeriodicalId":100196,"journal":{"name":"Brain and Development Case Reports","volume":"3 3","pages":"Article 100101"},"PeriodicalIF":0.0,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144861218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}