Publications by authors named "Yohane Miyata"

8 Publications

  • Page 1 of 1

Clinical and genetic characteristics of patients with Doose syndrome.

Epilepsia Open 2020 Sep 23;5(3):442-450. Epub 2020 Jul 23.

Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan.

Objective: To elucidate the genetic background and genotype-phenotype correlations for epilepsy with myoclonic-atonic seizures, also known as myoclonic-astatic epilepsy (MAE) or Doose syndrome.

Methods: We collected clinical information and blood samples from 29 patients with MAE. We performed whole-exome sequencing for all except one MAE case in whom custom capture sequencing identified a variant.

Results: We newly identified four variants: and missense variants and microdeletions at 2q24.2 involving and Xp22.31 involving . Febrile seizures preceded epileptic or afebrile seizures in four patients, of which two patients had gene variants. Myoclonic-atonic seizures occurred at onset in four patients, of which two had variants, and during the course of disease in three patients. Variants were more commonly identified in patients with a developmental delay or intellectual disability (DD/ID), but genetic status was not associated with the severity of DD/ID. Attention-deficit/hyperactivity disorder and autistic spectrum disorder were less frequently observed in patients with variants than in those with unknown etiology.

Significance: MAE patients had genetic heterogeneity, and and emerged as possible candidate causative genes. Febrile seizures prior to epileptic seizures and myoclonic-atonic seizure at onset indicate a genetic predisposition to MAE. Comorbid conditions were not related to genetic predisposition to MAE.
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http://dx.doi.org/10.1002/epi4.12417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469791PMC
September 2020

Prenatal clinical manifestations in individuals with variants.

J Med Genet 2020 Jul 30. Epub 2020 Jul 30.

Department of Pediatric Neurology, Bobath Memorial Hospital, Osaka, Osaka, Japan.

Background: Variants in the type IV collagen gene () cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with variants remain unclear.

Methods: We examined in 218 individuals with suspected /2-related brain defects. Among those arising from variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail.

Results: Pathogenic 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 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 gene testing should be considered when pathogenic variants are strongly suspected.
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http://dx.doi.org/10.1136/jmedgenet-2020-106896DOI Listing
July 2020

Assessment and Rating of Motor Cerebellar Ataxias With the Kinect v2 Depth Sensor: Extending Our Appraisal.

Front Neurol 2020 11;11:179. Epub 2020 Mar 11.

Movement Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.

Current assessment of patients with cerebellar disorders is based on conventional neurological examination that is dependent on subjective judgements. Quantitative measurement of cerebellar ataxias (CAs) is essential for assessment of evidence-based treatments and the monitoring of the progress or recovery of diseases. It may provide us a useful tool to navigate future treatments for ataxia. We developed a Kinect v2. sensor system with a novel algorithm to measure and evaluate movements for two tests of Scale for the Assessment and Rating of Ataxia (SARA): the nose-finger test and gait. For the nose-finger test, we evaluated and compared accuracy, regularities and smoothness in the movements of the index finger and the proximal limbs between cerebellar patients and control subjects. For the task of walking, we evaluated and compared stability between the two groups. The precision of the system for evaluation of movements was smaller than 2 mm. For the nose-finger test, the mildly affected patients tended to show more instability than the control subjects. For a severely affected patient, our system quantified the instability of movements of the index finger using kinematic parameters, such as fluctuations and average speed. The average speed appears to be the most sensitive parameter that contrasts between patients with CAs and control subjects. Furthermore, our system also detected the adventitious movements of more proximal body parts, such as the elbow, shoulder and head. Assessment of walking was possible only in patients with mild CAs. They demonstrated large sways and compensatory wide stances. These parameters appeared to show higher accuracy than SARA. This examiner-independent device measures movements of the points of interest of SARA more accurately than eye and further provides additional information about the ataxic movements (e.g., the adventitious movements of the elbow, shoulder and head in the nose-finger test and the wide-based walking with large oscillation in the gait task), which is out of the scope of SARA. Our new system enables more accurate scoring of SARA and further provides additional information that is not currently evaluated with SARA. Therefore, it provides an easier, more accurate and more systematic description of CAs.
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http://dx.doi.org/10.3389/fneur.2020.00179DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078683PMC
March 2020

Long-Term Evaluation of Low-Dose Betamethasone for Ataxia Telangiectasia.

Pediatr Neurol 2019 11 13;100:60-66. Epub 2019 May 13.

Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University (TMDU), Tokyo, Japan. Electronic address:

Background: Ataxia telangiectasia is an autosomal recessive disorder characterized by cerebellar ataxia, telangiectases, immune defects, and a predisposition to malignancy. Quality of life is severely impaired by neurological symptoms. However, curative options for the neurological symptoms are limited. Recent studies have demonstrated short-term improvement in neurological symptoms with betamethasone therapy. However, the long-term and adverse effects of betamethasone are unclear. The aim of this study was to evaluate the long-term effects, benefits, and adverse effects of low-dose betamethasone in ataxia telangiectasia.

Methods: Six patients with ataxia telangiectasia received betamethasone at 0.02 mg/kg/day for two years. After cessation of betamethasone, the patients were observed for two additional years. Neurological assessments were performed, and adverse effects were monitored every three months throughout the four-year study period.

Results: Transient improvement of neurological symptom was observed in five of the six patients. However, after two years betamethasone treatment, only one of the six patients showed a slight improvement in the neurological score, one patient showed no change, and the neurological scores of the remaining four patients deteriorated. After the cessation of betamethasone treatment, neurological symptoms worsened in all patients. As an adverse effect of betamethasone, transient adrenal dysfunction was observed in all cases.

Conclusions: Although these findings are in agreement with previous studies suggesting that short-term betamethasone treatment transiently benefits patients with ataxia telangiectasia, the long-term benefits and risks should be carefully considered.
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http://dx.doi.org/10.1016/j.pediatrneurol.2019.05.006DOI Listing
November 2019

Comprehensive analysis of coding variants highlights genetic complexity in developmental and epileptic encephalopathy.

Nat Commun 2019 06 7;10(1):2506. Epub 2019 Jun 7.

Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.

Although there are many known Mendelian genes linked to epileptic or developmental and epileptic encephalopathy (EE/DEE), its genetic architecture is not fully explained. Here, we address this incompleteness by analyzing exomes of 743 EE/DEE cases and 2366 controls. We observe that damaging ultra-rare variants (dURVs) unique to an individual are significantly overrepresented in EE/DEE, both in known EE/DEE genes and the other non-EE/DEE genes. Importantly, enrichment of dURVs in non-EE/DEE genes is significant, even in the subset of cases with diagnostic dURVs (P = 0.000215), suggesting oligogenic contribution of non-EE/DEE gene dURVs. Gene-based analysis identifies exome-wide significant (P = 2.04 × 10) enrichment of damaging de novo mutations in NF1, a gene primarily linked to neurofibromatosis, in infantile spasm. Together with accumulating evidence for roles of oligogenic or modifier variants in severe neurodevelopmental disorders, our results highlight genetic complexity in EE/DEE, and indicate that EE/DEE is not an aggregate of simple Mendelian disorders.
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http://dx.doi.org/10.1038/s41467-019-10482-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6555845PMC
June 2019

Periventricular small cystic lesions in a patient with Coffin-Lowry syndrome who exhibited a novel mutation in the RPS6KA3 gene.

Brain Dev 2018 Aug 17;40(7):566-569. Epub 2018 Apr 17.

Department of Human Genetics, Yokohama City University Graduate School of Medicine, Kanagawa, Japan.

Background: Coffin-Lowry syndrome is a rare X-linked disease, caused by loss-of-function mutations in the RPS6KA3 gene. Patients exhibit severe intellectual disability with characteristic dysmorphism. As there are no specific laboratory findings to support the diagnosis of Coffin-Lowry syndrome, it may be difficult to diagnose-especially in young children, where the characteristic craniofacial features are less discernible.

Case: Here we report on a 2-year-old boy with Coffin-Lowry syndrome with a novel missense mutation in the RPS6KA3 gene. On magnetic resonance imaging, his brain exhibited periventricular signal abnormalities with multiple small cystic lesions. These findings may aid in diagnosis of Coffin-Lowry syndrome.
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http://dx.doi.org/10.1016/j.braindev.2018.03.012DOI Listing
August 2018

Factors associated with antisocial behavior in patients with developmental disorder.

No To Hattatsu 2016 Jul;48(4):259-64

Objective: This study investigated the factors associated with antisocial behavior (AB) in children with developmental disorder and effective treatments. Methods: Participants were 110 schoolchildren with developmental disorder and with or without accompanying AB who visited our hospital between October 2009 and October 2012. Among the children with AB, those who exhibited one or more symptoms of conduct disorder (CD) were assigned to the CD subgroup. We examined the background characteristics, past history, type of antisocial behavior, and symptom improvement after treatment in the children with AB and compared the relevant factors with children with developmental disorder without AB. Results: Of the 110 participants, 72 (65.5%) did not exhibit AB and 38 (34.5%) did, 7 (5.5%) of whom fulfilled the criteria for CD. Compared to the children without AB, the children with AB showed a significantly higher occurrence of attention deficit/hyperactivity disorder (AD/HD), maltreatment, institutionalization due to maltreatment, parental mental/psychological problems, and family instability. After medical treatment combined with social-skills training and parental education, 22 of the 38 children with AB showed improved behavior. In the CD subgroup, 4 children were diagnosed with AD/HD and 3 with pervasive developmental disorder, and none of the 7 improved with treatment. Conclusion: AB was associated with AD/HD, maltreatment, institutionalization, parental mental/psychological problems, and family instability. The most effective therapy was parental education. Children with AB need early intervention given that those who already exhibited symptoms of CD showed little improvement with treatment.
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July 2016

[Nonconvulsive status epilepticus as an initial symptom in a boy with frontal lobe epilepsy].

No To Hattatsu 2014 Jul;46(4):301-6

An 11-year-old boy, who had no remarkable past history, exhibited disorientation and abnormal behavior lasting for several hours. Continuous ictal discharges on his EEG lead to the diagnosis of nonconvulsive status epilepticus (NCSE). The administration of diazepam instantly resulted in the cessation of ictal discharges, associated with clinical recovery. Interictal spikes distributed in frontal lobes are sporadically seen, suggesting frontal lobe as an epileptic focus. After starting medication, he showed excellent clinical course without recurrence of seizure or neurological sequelae. Although NCSE is generally suggestive of poor prognosis, some subtypes of NCSE, such as partial status epilepticus and absence status epilepticus, are not always associated with adverse outcome. The present case suggests that epileptic patients who present NCSE at onset and lack interictal neurological impairments might have good outcome.
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July 2014