Publications by authors named "Katsuyuki Yokoi"

The hyper-unstable Chr9p21 locus, harbouring the interferon gene cluster, oncogenes and , is linked to multiple diseases. (GGGGCC)n expansions (Exp) are associated with incompletely penetrant amyotrophic lateral sclerosis, frontotemporal dementia and autoimmune disorders. Exp patients display hyperactive cGAS-STING-linked interferon immune and DNA damage responses, but the source of immunostimulatory or damaged DNA is unknown.

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The hyper-unstable Chr9p21 locus, harbouring the interferon gene cluster, oncogenes and is linked to multiple diseases. (GGGGCC)n expansions ( Exp) are associated with incompletely penetrant amyotrophic lateral sclerosis, frontotemporal dementia and autoimmune disorders. Exp patients display hyperactive cGAS-STING-linked interferon immune and DNA damage responses, but the source of immuno-stimulatory or damaged DNA is unknown.

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Mutations in transport and Golgi organization 2 homolog () have recently been described as a cause of an autosomal recessive syndrome characterized by episodes of metabolic crisis associated with rhabdomyolysis, cardiac arrhythmias, and neurodegeneration. Herein, we report a case of a one-and-a-half-year-old Japanese girl, born to nonconsanguineous parents, who presented with metabolic crisis characterized by hypoglycemia with hypoketonemia, rhabdomyolysis, lactic acidosis, and prolonged corrected QT interval (QTc) at the age of 6 months. Acylcarnitine analysis during the episode of crisis showed prominent elevation of C14:1, suggesting very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency.

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Maple syrup urine disease (MSUD) is a rare autosomal recessive inherited disorder of branched-chain amino acid metabolism caused by mutations in , , and that encode the E1α, E1β, and E2 subunits of the branched-chain α-ketoacid dehydrogenase (BCKD) complex. Various MSUD-causing variants have been described; however, no structural rearrangements in have been reported to cause the classic MSUD phenotype. Here, we describe the classic patient with MSUD with compound heterozygous pathogenic variants in : a missense variant (NM_000709.

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Article Synopsis
  • * A case study of a nine-month-old boy revealed that he suffered from refractory nephrotic syndrome and complications from spTMA, along with a heterozygous mutation in the complement factor-I gene and a deletion affecting complement regulation.
  • * Despite treatment with Eculizumab, which temporarily improved his condition, the boy experienced severe complications including cardiac arrest and was later declared brain dead, highlighting the diagnostic difficulties and the complex interplay between
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  • * A 13-year-old Japanese girl experienced diabetic ketoacidosis and poor insulin secretion, but improved after starting insulin treatment, requiring no further treatment for 2 years until a recurrence occurred at age 15.
  • * The ongoing fluctuations in her insulin production suggested MODY, yet her case deviates from typical MODY8 presentations as it showed no exocrine dysfunction despite having a significant mutation in the CEL gene, indicating a potential link between her specific mutation
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Urea cycle disorders (UCDs), inborn errors of hepatocyte metabolism, cause hyperammonemia and lead to neurocognitive deficits, coma, and even death. Sodium 4-phenylbutyrate (NaPB), a standard adjunctive therapy for UCDs, generates an alternative pathway of nitrogen deposition through glutamine consumption. Administration during or immediately after a meal is the approved usage of NaPB.

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Article Synopsis
  • - A 13-year-old boy was diagnosed with arginase 1 deficiency, linked to two specific genetic variants in the ARG1 gene.
  • - Sanger sequencing revealed the variants as NM_000045.4: c.365G>A (p.Trp122*) and c.820G>A (p.Asp274Asn), with the latter being a new and unreported variant.
  • - The p.Asp274Asn variant is considered highly pathogenic due to its location in a critical area of the protein, and the boy's arginase activity was found to be extremely low.
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Cancer treatment with a fluoropyrimidine (FP) is often accompanied by severe toxicity that may be dependent on the activity of catalytic enzymes encoded by the DPYD, DPYS, and UPB1 genes. Genotype-guided dose individualization of FP therapy has been proposed in western countries, but our knowledge of the relevant genetic variants in East Asian populations is presently limited. To investigate the association between these genetic variations and FP-related high toxicity in a Japanese population, we obtained blood samples from 301 patients who received this chemotherapy and sequenced the coding exons and flanking intron regions of their DPYD, DPYS, and UPB1 genes.

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Background: Hypophosphatasia (HPP) is a rare inborn error of metabolism that results from a dysfunctional tissue non-specific alkaline phosphatase enzyme (TNSALP). Although genotype-phenotype correlations have been described in HPP patients, only sparse information is currently available on the genetics of mild type HPP.

Methods: We investigated 5 Japanese patients from 3 families with mild HPP (patients 1 and 2 are siblings; patient 4 is a daughter of patient 5) who were referred to Fujita Health University due to the premature loss of deciduous teeth.

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Background: Several immunosuppressants have been used to treat children with steroid-dependent nephrotic syndrome (SDNS). Mizoribine (MZR) is an immunosuppressant used to maintain remission in children with SDNS, although its effectiveness for treating SDNS remains controversial. Therefore, in this study, we assessed the clinical factors associated with children having SDNS who were successfully treated with MZR.

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Background: Ornithine transcarbamylase deficiency (OTCD) is an X-linked recessive disorder involving a defect in the urea cycle caused by OTC gene mutations. Although a total of 417 disease-causing mutations in OTC have been reported, structural abnormalities in this gene are rare. We here describe a female OTCD case caused by an exonic duplication of the OTC gene (exons 1-6).

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Phosphoglucomutase 1 (PGM1) deficiency is a recently defined disease characterized by glycogenosis and a congenital glycosylation disorder caused by recessive mutations in the PGM1 gene. We report a case of a 12-year-old boy with first-cousin parents who was diagnosed with a PGM1 deficiency due to significantly decreased PGM1 activity in his muscle. However, Sanger sequencing revealed no pathogenic mutation in the PGM1 gene in this patient.

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