Seiji Mizuno

Aichi Human Service Center

Topics (10) View all

Publications (32) View all

  • Article: Clinical Correlations of Mutations Affecting Six Components of the SWI/SNF Complex: Detailed Description of 21 Patients and a Review of the Literature.
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    ABSTRACT: Mutations in the components of the SWItch/sucrose nonfermentable (SWI/SNF)-like chromatin remodeling complex have recently been reported to cause Coffin-Siris syndrome (CSS), Nicolaides-Baraitser syndrome (NCBRS), and ARID1B-related intellectual disability (ID) syndrome. We detail here the genotype-phenotype correlations for 85 previously published and one additional patient with mutations in the SWI/SNF complex: four with SMARCB1 mutations, seven with SMARCA4 mutations, 37 with SMARCA2 mutations, one with an SMARCE1 mutation, three with ARID1A mutations, and 33 with ARID1B mutations. The mutations were associated with syndromic ID and speech impairment (severe/profound in SMARCB1, SMARCE1, and ARID1A mutations; variable in SMARCA4, SMARCA2, and ARID1B mutations), which was frequently accompanied by agenesis or hypoplasia of the corpus callosum. SMARCB1 mutations caused "classical" CSS with typical facial "coarseness" and significant digital/nail hypoplasia. SMARCA4 mutations caused CSS without typical facial coarseness and with significant digital/nail hypoplasia. SMARCA2 mutations caused NCBRS, typically with short stature, sparse hair, a thin vermillion of the upper lip, an everted lower lip and prominent finger joints. A SMARCE1 mutation caused CSS without typical facial coarseness and with significant digital/nail hypoplasia. ARID1A mutations caused the most severe CSS with severe physical complications. ARID1B mutations caused CSS without typical facial coarseness and with mild digital/nail hypoplasia, or caused syndromic ID. Because of the common underlying mechanism and overlapping clinical features, we propose that these conditions be referred to collectively as "SWI/SNF-related ID syndromes". © 2013 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 05/2013; · 2.39 Impact Factor
  • Article: Molecular and clinical studies in 138 Japanese patients with silver-russell syndrome.
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    ABSTRACT: BACKGROUND: Recent studies have revealed relative frequency and characteristic phenotype of two major causative factors for Silver-Russell syndrome (SRS), i.e. epimutation of the H19-differentially methylated region (DMR) and uniparental maternal disomy 7 (upd(7)mat), as well as multilocus methylation abnormalities and positive correlation between methylation index and body and placental sizes in H19-DMR epimutation. Furthermore, rare genomic alterations have been found in a few of patients with idiopathic SRS. Here, we performed molecular and clinical findings in 138 Japanese SRS patients, and examined these matters. METHODOLOGYPRINCIPAL FINDINGS: We identified H19-DMR epimutation in cases 1-43 (group 1), upd(7)mat in cases 44-52 (group 2), and neither H19-DMR epimutation nor upd(7)mat in cases 53-138 (group 3). Multilocus analysis revealed hyper- or hypomethylated DMRs in 2.4% of examined DMRs in group 1; in particular, an extremely hypomethylated ARHI-DMR was identified in case 13. Oligonucleotide array comparative genomic hybridization identified a ∼3.86 Mb deletion at chromosome 17q24 in case 73. Epigenotype-phenotype analysis revealed that group 1 had more reduced birth length and weight, more preserved birth occipitofrontal circumference (OFC), more frequent body asymmetry and brachydactyly, and less frequent speech delay than group 2. The degree of placental hypoplasia was similar between the two groups. In group 1, the methylation index for the H19-DMR was positively correlated with birth length and weight, present height and weight, and placental weight, but with neither birth nor present OFC. CONCLUSIONSSIGNIFICANCE: The results are grossly consistent with the previously reported data, although the frequency of epimutations is lower in the Japanese SRS patients than in the Western European SRS patients. Furthermore, the results provide useful information regarding placental hypoplasia in SRS, clinical phenotypes of the hypomethylated ARHI-DMR, and underlying causative factors for idiopathic SRS.
    PLoS ONE 01/2013; 8(3):e60105. · 4.09 Impact Factor
  • Article: Clinical and radiological features of Japanese patients with a severe phenotype due to CASK mutations.
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    ABSTRACT: Heterozygous loss of function mutations of CASK at Xp11.4 in females cause severe intellectual disability (ID) and microcephaly with pontine and cerebellar hypoplasia (MICPCH). However, the longitudinal clinical and radiological course of affected patients, including patterns of postnatal growth, has not been described. Neurodevelopmental and imaging information was retrospectively accrued for 16 Japanese (15 female and 1 male) patients with ID and MICPCH associated with CASK mutations. All records were analyzed; patient age ranged from 2 to 16 years at the time of the most recent examinations. The growth pattern, neurological development, neurological signs/symptoms, and facial features were similar in the 15 female patients. Their head circumference at birth was within the normal range in about half, and their height and weight were frequently normal. This was followed by early development of severe microcephaly and postnatal growth retardation. The patients acquired head control almost normally between 3 and 6 months, followed by motor delay. More than half of the female patients had epilepsy. Their MRIs showed microcephaly, brainstem, and cerebellar hypoplasia in early infancy, and a normal or large appearing corpus callosum. The male patient showed a more severe clinical phenotype. These uniform clinical and radiological features should facilitate an early diagnosis and be useful for medical care of females with ID and MICPCH associated with CASK mutations. © 2012 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 11/2012; · 2.39 Impact Factor
  • Article: KDM6A Point Mutations Cause Kabuki Syndrome.
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    ABSTRACT: Kabuki syndrome (KS) is a rare congenital anomaly syndrome characterized by a unique facial appearance, growth retardation, skeletal abnormalities, and intellectual disability. In 2010, MLL2 was identified as a causative gene. On the basis of published reports, 55-80% of KS cases can be explained by MLL2 abnormalities. Recently, de novo deletion of KDM6A has been reported in three KS patients, but point mutations of KDM6A have never been found. In this study, we investigated KDM6A in 32 KS patients without an MLL2 mutation. We identified two nonsense mutations and one 3-bp deletion of KDM6A in three KS cases. This is the first report of KDM6A point mutations associated with KS.
    Human Mutation 10/2012; · 5.69 Impact Factor
  • Article: Age-dependent change in behavioral feature in Rubinstein-Taybi syndrome.
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    ABSTRACT: Rubinstein-Taybi syndrome (RTS) is characterized by developmental delay, postnatal growth retardation, typical facial appearance, and broad thumbs and big toes. The behavioral phenotype of children with RTS has been described as friendly and having good social contacts; however, a short attention span and hyperactivity are sometimes present. Little attention has been paid to the behavioral aspects of adults with RTS. We conducted an observational study focusing on behavioral problems in adolescents and adults with RTS compared with children with RTS. A total of 63 patients with RTS and their caretakers answered self-administered questionnaires regarding behavioral features including the Child Behavior Checklist (CBCL). High total CBCL scores were observed, and the mean score was beyond the clinical cut-off point. After stratification into two groups according to age, the older group (≥14 years) displayed statistically significant higher scores for Anxious/Depression (P = 0.002) and Aggressive Behavior (P = 0.036) than the younger group (≤13 years). In analyses of single items, statistically significant differences between the younger group and the older group were found for 'Nervous, high-strung, or tense' (31.3% vs 67.7%, P = 0.004) and 'Too fearful or anxious' (37.5% vs 64.5%, P = 0.032). Here, we showed that the specific behavioral phenotypes of RTS change during adolescence, with anxiety, mood instability, and aggressive behavior emerging as patients age. A clear need exists to follow-up patients with RTS to catch the eventual emergence of psychiatric problems with age. If necessary, pharmacological treatment should be considered.
    Congenital Anomalies 06/2012; 52(2):82-6.

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