Publications by authors named "Masano Amamoto"

10 Publications

  • Page 1 of 1

Crohn's disease and chronic recurrent multifocal osteomyelitis in a Japanese boy.

Pediatr Int 2021 Jan 27;63(1):115-117. Epub 2020 Dec 27.

Departments of Pediatrics and Child Health, Kurume University School of Medicine, Kurume, Japan.

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http://dx.doi.org/10.1111/ped.14370DOI Listing
January 2021

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

Parotid gland atrophy after conservative treatment of a post-traumatic parotid fistula in a two-year-old boy.

Int J Pediatr Otorhinolaryngol 2020 Nov 22;138:110326. Epub 2020 Aug 22.

Children's Medical Center, Kitakyushu City Yahata Hospital, 2-6-2 Ogura, Yahatahigashi-ku, Kitakyushu City, Fukuoka, 805-8534, Japan. Electronic address:

A parotid fistula is a rare complication following parotid gland and duct injury. A two-year-old boy with a previous parotid fistula after parotid injury due to a dog bite was successfully treated with pressure-dressing therapy, which is generally non-invasive and tolerable by young children. During follow-up, ultrasonography revealed atrophy of the parotid gland. This finding is consistent with the healing mechanism previously assumed in adult patients with a parotid fistula. Consideration should be paid to the possibility of oral environmental changes associated with reduced saliva secretion from parotid gland atrophy after conservative treatment of parotid fistula.
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http://dx.doi.org/10.1016/j.ijporl.2020.110326DOI Listing
November 2020

Nasopharyngeal airway for upper airway obstruction in infectious mononucleosis.

Pediatr Int 2020 05 28;62(5):642-643. Epub 2020 Apr 28.

Children's Medical Center, Kitakyushu City Yahata Hospital, Kitakyushu City, Fukuoka, Japan.

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http://dx.doi.org/10.1111/ped.14143DOI Listing
May 2020

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

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

J Med Genet 2019 06 6;56(6):396-407. Epub 2019 Mar 6.

Division of Pediatrics, Tokyo Metropolitan Tobu Medical Center for Persons with Developmental and Multiple Disabilities, Tokyo, Japan.

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 (). Our objective to investigate the genetic landscape of -negative typical/atypical RTT and RTT-like phenotypes using whole exome sequencing (WES).

Methods: We performed WES on 77 -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 ) 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 (), ubiquitin-specific peptidase 8 () and microtubule-associated serine/threonine kinase 3 (), as well as biallelic variants in nuclear receptor corepressor 2 ().

Conclusions: Our study provides a new landscape including additional genetic variants contributing to RTT-like phenotypes, highlighting the importance of comprehensive genetic analysis.
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http://dx.doi.org/10.1136/jmedgenet-2018-105775DOI Listing
June 2019

Autosomal-Recessive Mutations in AP3B2, Adaptor-Related Protein Complex 3 Beta 2 Subunit, Cause an Early-Onset Epileptic Encephalopathy with Optic Atrophy.

Am J Hum Genet 2016 Dec 23;99(6):1368-1376. Epub 2016 Nov 23.

Department of Paediatrics, Faculty of Medicine, Jordan University, Amman 11942, Jordan.

Early-onset epileptic encephalopathy (EOEE) represents a heterogeneous group of severe disorders characterized by seizures, interictal epileptiform activity with a disorganized electroencephalography background, developmental regression or retardation, and onset before 1 year of age. Among a cohort of 57 individuals with epileptic encephalopathy, we ascertained two unrelated affected individuals with EOEE associated with developmental impairment and autosomal-recessive variants in AP3B2 by means of whole-exome sequencing. The targeted sequencing of AP3B2 in 86 unrelated individuals with EOEE led to the identification of an additional family. We gathered five additional families with eight affected individuals through the Matchmaker Exchange initiative by matching autosomal-recessive mutations in AP3B2. Reverse phenotyping of 12 affected individuals from eight families revealed a homogeneous EOEE phenotype characterized by severe developmental delay, poor visual contact with optic atrophy, and postnatal microcephaly. No spasticity, albinism, or hematological symptoms were reported. AP3B2 encodes the neuron-specific subunit of the AP-3 complex. Autosomal-recessive variations of AP3B1, the ubiquitous isoform, cause Hermansky-Pudlak syndrome type 2. The only isoform for the δ subunit of the AP-3 complex is encoded by AP3D1. Autosomal-recessive mutations in AP3D1 cause a severe disorder cumulating the symptoms of the AP3B1 and AP3B2 defects.
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http://dx.doi.org/10.1016/j.ajhg.2016.10.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5142104PMC
December 2016

Targeted capture and sequencing for detection of mutations causing early onset epileptic encephalopathy.

Epilepsia 2013 Jul 10;54(7):1262-9. Epub 2013 May 10.

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

Purpose: Early onset epileptic encephalopathies (EOEEs) are heterogeneous epileptic disorders caused by various abnormalities in causative genes including point mutations and copy number variations (CNVs). In this study, we performed targeted capture and sequencing of a subset of genes to detect point mutations and CNVs simultaneously.

Methods: We designed complementary RNA oligonucleotide probes against the coding exons of 35 known and potential candidate genes. We tested 68 unrelated patients, including 15 patients with previously detected mutations as positive controls. In addition to mutation detection by the Genome Analysis Toolkit, CNVs were detected by the relative depth of coverage ratio. All detected events were confirmed by Sanger sequencing or genomic microarray analysis.

Key Findings: We detected all positive control mutations. In addition, in 53 patients with EOEEs, we detected 12 pathogenic mutations, including 9 point mutations (2 nonsense, 3 splice-site, and 4 missense mutations), 2 frameshift mutations, and one 3.7-Mb microdeletion. Ten of the 12 mutations occurred de novo; the other two had been previously reported as pathogenic. The entire process of targeted capture, sequencing, and analysis required 1 week for the testing of up to 24 patients.

Significance: Targeted capture and sequencing enables the identification of mutations of all classes causing EOEEs, highlighting its usefulness for rapid and comprehensive genetic testing.
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http://dx.doi.org/10.1111/epi.12203DOI Listing
July 2013

Post-natal treatment by a blood-brain-barrier permeable calpain inhibitor, SNJ1945 rescued defective function in lissencephaly.

Sci Rep 2013 6;3:1224. Epub 2013 Feb 6.

Department of Genetic Disease Research, Osaka City University Graduate School of Medicine, Asahi-machi 1-4-3 Abeno, Osaka 545-8586, Japan.

Toward a therapeutic intervention of lissencephaly, we applied a novel calpain inhibitor, SNJ1945. Peri-natal or post-natal treatment with SNJ1945 rescued defective neuronal migration in Lis1⁺/⁻ mice, impaired behavioral performance and improvement of ¹⁸F-FDG uptake. Furthermore, SNJ1945 improved the neural circuit formation and retrograde transport of NFG in Lis1⁺/⁻ mice. Thus, SNJ1945 is a potential drug for the treatment of human lissencephaly patients.
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http://dx.doi.org/10.1038/srep01224DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565454PMC
August 2013

Clinical study of childhood acute disseminated encephalomyelitis, multiple sclerosis, and acute transverse myelitis in Fukuoka Prefecture, Japan.

Brain Dev 2010 Jun 25;32(6):454-62. Epub 2009 Nov 25.

Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.

Acute disseminated encephalomyelitis (ADEM) has recently been studied in several countries owing to the development and wide spread use of imaging technology, but few epidemiological studies of childhood ADEM have been undertaken in Asian countries. To perform a comprehensive survey of ADEM and related diseases in Japanese children, we conducted a multicenter, population-based study on childhood ADEM, multiple sclerosis, and acute isolated transverse myelitis in Fukuoka Prefecture, Japan. We identified 26 children with ADEM, 8 with multiple sclerosis, and 4 with acute transverse myelitis during 5 years between September 1998 and August 2003. The incidence of childhood ADEM under the age of 15 years was 0.64 per 100,000 person-years, mean age at onset was 5.7 years, and male-female ratio was 2.3:1. The prevalence of childhood multiple sclerosis was 1.3 per 100,000 persons. The mean age at onset of multiple sclerosis, 9.3 years, was significantly higher than that of ADEM. Nineteen (73%) and four (15%) patients with ADEM experienced antecedent infectious illnesses and vaccinations, respectively, within 1 month before the onset. Clinical and radiological findings of ADEM revealed that the frequency of seizures, mean white blood cell counts in cerebrospinal fluid, and the frequency of subcortical lesions in Fukuoka study, seemed to be higher than those in previous non-Asian studies. These findings suggest that there are ethnic or geographical differences in the incidence and clinical features of ADEM, and that there might be potent genetic or environmental risk factors for ADEM distinct from those for multiple sclerosis.
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http://dx.doi.org/10.1016/j.braindev.2009.10.006DOI Listing
June 2010