M Kato

Yamagata University, Ямагата, Yamagata, Japan

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Publications (6)27.56 Total impact

  • Clinical Genetics 06/2013; · 3.65 Impact Factor
  • No to hattatsu. Brain and development 01/2013; 45(1):64-6.
  • Clinical Genetics 12/2011; 81(4):399-402. · 3.65 Impact Factor
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    ABSTRACT: Ohtahara syndrome (OS) is one of the most severe and earliest forms of epilepsy. We have recently identified that the de novo mutations of STXBP1 are important causes for OS. Here we report a paternal somatic mosaicism of an STXBP1 mutation. The affected daughter had onset of spasms at 1 month of age, and interictal electroencephalogram showed suppression-burst pattern, leading to the diagnosis of OS. She had a heterozygous c.902+5G>A mutation of STXBP1, which affects donor splicing of exon 10, resulting in 138-bp insertion of intron 10 sequences in the transcript. The mutant transcript had a premature stop codon, and was degraded by nonsense-mediated mRNA decay in lymphoblastoid cells derived from the patient. High-resolution melting analysis of clinically unaffected parental DNAs suggested that the father was somatic mosaic for the mutation, which was also suggested by sequencing. Cloning of PCR products amplified with the paternal DNA samples extracted from blood, saliva, buccal cells, and nails suggested that 5.3%, 8.7%, 11.9%, and 16.9% of alleles harbored the mutation, respectively. This is a first report of somatic mosaicism of an STXBP1 mutation, which has implications in genetic counseling of OS.
    Clinical Genetics 10/2010; 80(5):484-8. · 3.65 Impact Factor
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    ABSTRACT: ARX is a paired-type homeobox gene located on the X chromosome that contains five exons with four polyalanine (PolyA) tracts, a homeodomain, and a conserved C-terminal aristaless domain. Studies in humans have demonstrated remarkable pleiotropy: malformation phenotypes are associated with protein truncation mutations and missense mutations in the homeobox; nonmalformation phenotypes, including X-linked infantile spasms (ISS), are associated with missense mutations outside of the homeobox and expansion of the PolyA tracts. To investigate the role of ARX, we performed mutation analysis in 115 boys with cryptogenic ISS. This included two pairs of brothers. We found an expansion of the trinucleotide repeat that codes for the first PolyA tract from 10 to 17 GCG repeats (c.333_334ins[GCG]7) in six boys (5.2%) ages 2 to 14, from four families, including the two pairs of brothers. In addition to ISS, all six boys had severe mental retardation and generalized dystonia that appeared around the age of 6 months and worsened, eventually leading to stable severe quadriplegic dyskinesia within age 2 years. Three children experienced recurrent, life-threatening status dystonicus. In four children brain MRI showed multiple small foci of abnormal cavitation on T1 and increased signal intensity on T2 in the putamina, possibly reflecting progressive multifocal loss of tissue. The phenotype of infantile spasms with severe dyskinetic quadriparesis increases the number of human disorders that result from the pathologic expansion of single alanine repeats. ARX gene testing should be considered in boys with infantile spasms and dyskinetic cerebral palsy in the absence of a consistent perinatal history.
    Neurology 08/2007; 69(5):427-33. · 8.30 Impact Factor
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    ABSTRACT: Patients with encephalopathy heralded by a prolonged seizure as the initial symptom often have abnormal subcortical white matter on diffusion-weighted MRI (DWI). To determine if these patients share other common features. Patients with encephalopathy heralded by a prolonged seizure and followed by the identification of abnormal subcortical white matter on MRI were collected retrospectively. Their clinical, laboratory, and radiologic data were reviewed. Seventeen patients were identified, ages 10 months to 4 years. All had a prolonged febrile seizure (longer than 1 hour in 12 patients) as their initial symptom. Subsequent seizures, most often in clusters of complex partial seizures, were seen 4 to 6 days after the initial seizure in 16 patients. Outcome ranged from almost normal to severe mental retardation. MRI performed within 2 days of presentation showed no abnormality. Subcortical white matter lesions were observed on DWI between 3 and 9 days in all 17 patients. T2-weighted images showed linear high intensity of subcortical U fibers in 13 patients. The lesions were predominantly frontal or frontoparietal in location with sparing of the perirolandic region. The diffusion abnormality disappeared between days 9 and 25, and cerebral atrophy was detected later than 2 weeks. Three patients having only frontal lesions had relatively good clinical outcome. Although the pathophysiologic mechanism remains unknown, these patients seem to have a distinctive encephalopathy syndrome. MRI is helpful in establishing the diagnosis of this encephalopathy.
    Neurology 06/2006; 66(9):1304-9; discussion 1291. · 8.30 Impact Factor