Publications by authors named "Saitsu H"

Interferon regulatory factor 2 binding protein-like (IRF2BPL) is a single-exon gene that is ubiquitously expressed in various tissues, including the brain. IRF2BPL encodes a transcription factor with two zinc-finger domains that potentially downregulate WNT signaling in the nervous system. Pathogenic IRF2BPL variants have been reported to cause developmental delay, seizures, myoclonus epilepsies, autistic spectrum disorder, and other neurodevelopmental disorders.

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Background: Uniparental isodisomy (UPiD) refers to a condition, in which both homologous chromosomes are inherited from only one parental homolog, which can result in either imprinting disorders or autosomal recessive conditions.

Methods: We performed chromosomal microarray analysis, exome sequencing (ES), and RNA sequencing (RNA-seq) using the patient's urine-derived cells on a patient with growth retardation and multiple congenital anomalies.

Results: We identified a homozygous ~0.

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Article Synopsis
  • Brain development involves the coordinated growth of structures necessary for forming neural circuits, with the corpus callosum being a crucial connection between brain hemispheres.
  • Defects in the growth process, particularly in the development of callosal projection neurons, can lead to syndromic corpus callosum dysgenesis (CCD) and are associated with other conditions like microcephaly.
  • The study identifies WDR47 as a key gene responsible for survival of callosal neurons and highlights its role in mitochondrial and microtubule maintenance, suggesting that mutations in this gene lead to a new neurodevelopmental syndrome involving corpus callosum abnormalities.
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Smoc1 and Smoc2, members of the SPARC family of genes, encode signaling molecules downstream of growth factors such as the TGF-β, FGF, and PDGF families. Smoc1 has been implicated in playing a crucial role in microphthalmia with limb anomalies in humans and mice, while Smoc2 deficiency causes dental developmental defects. Although developmental cytokines/growth factors including TGF-β superfamily have been shown to play critical roles in postnatal spermatogenesis, there are no reports analyzing the spatial and temporal expression of Smoc1 and Smoc2 in the postnatal testis.

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Background: CLCN2-related leukoencephalopathy (CC2L) is a rare autosomal recessive disorder caused by biallelic variants of CLCN2, which encodes chloride channel 2. Although CC2L is associated with distinct radiological features, it presents with a wide range of clinical features.

Case Presentation: A 34-year-old woman presented to our hospital with a sudden onset of vertigo with headache.

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Variant annotations are crucial for efficient identification of pathogenic variants. In this study, we retrospectively analyzed the utility of four annotation tools (allele frequency, ClinVar, SpliceAI, and Phenomatcher) in identifying 271 pathogenic single nucleotide and small insertion/deletion variants (SNVs/small indels). Although variant filtering based on allele frequency is essential for narrowing down on candidate variants, we found that 13 de novo pathogenic variants in autosomal dominant or X-linked dominant genes are registered in gnomADv4.

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Male infertility can be caused by chromosomal abnormalities, mutations and epigenetic defects. Epigenetic modifiers pre-program hundreds of spermatogenic genes in spermatogonial stem cells (SSCs) for expression later in spermatids, but it remains mostly unclear whether and how those genes are involved in fertility. Here, we report that Wfdc15a, a WFDC family protease inhibitor pre-programmed by KMT2B, is essential for spermatogenesis.

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Lissencephaly is a rare brain malformation characterized by abnormal neuronal migration during cortical development. In this study, we performed a comprehensive genetic analysis using next-generation sequencing in 12 unsolved Japanese lissencephaly patients, in whom PAFAH1B1, DCX, TUBA1A, and ARX variants were excluded using the Sanger method. Exome sequencing (ES) was conducted on these 12 patients, identifying pathogenic variants in CEP85L, DYNC1H1, LAMC3, and DCX in four patients.

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Article Synopsis
  • Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative condition linked to GGC repeat expansions in the NOTCH2NLC gene, with potential impacts on various organs, including the kidneys.
  • A study on a family with NIID found that four out of five members experienced proteinuria and had a renal pathology diagnosis of focal segmental glomerulosclerosis (FSGS), alongside other neurological symptoms.
  • Advanced genetic analyses, including exome and whole-genome sequencing, identified STR expansions in NOTCH2NLC, indicating a possible connection between this genetic alteration and renal diseases.
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  • The article discusses a third case of chloride voltage-gated channel 2 (CLCN2)-related leukoencephalopathy (CC2L) identified in Japan, where the patient experienced symptoms like headache, vertigo, and mild visual impairment.
  • The specific genetic variant in the patient, NM_004366.6:c.61dup, p.(Leu21Profs*27), was found to be relatively common among Japanese patients, as it has also appeared in two other cases.
  • MRI indicated changes in brain structure, while magnetic resonance spectroscopy (MRS) provided new insights by revealing decreased choline levels in the white matter, underscoring MRS's greater sensitivity compared to MRI.
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Heterozygous transmembrane protein 63A (TMEM63A) variants cause transient infantile hypomyelinating leukodystrophy-19, which features remarkable natural resolution of clinical and imaging findings during childhood. Previous reports have mainly described de novo variants lacking detailed familial cases. Herein, we describe the clinical course of familial cases with a TMEM63A variant.

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Epileptic seizures can be worsened by infections; however, they sometimes disappear or decrease after an acute viral infection, although this is rare. We report the spontaneous remission of epileptic seizures following norovirus-induced viral gastroenteritis in a boy with encephalopathy. He had clonic seizures daily from the age of two months and developed epileptic spasms at 14 months of age; he was admitted to the hospital at this time.

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Silver-Russell syndrome (SRS) is a representative imprinting disorder characterized by pre- and postnatal growth failure. We encountered two Japanese SRS cases with a de novo pathogenic frameshift variant of HMGA2 (NM_003483.6:c.

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Article Synopsis
  • - KIF1A-related disorders (KRDs) involve a range of genetic variants with diverse clinical presentations, and recent research has broadened our understanding of heterozygous KIF1A variants, although long-term studies are limited.
  • - A study at Miyagi Children's Hospital reviewed records of six patients with heterozygous KIF1A variants who had spastic paraplegia, tracking their clinical symptoms and background over an average follow-up of 30 years.
  • - Key findings showed that early signs include developmental delays and gait issues, with later symptoms progressing to spastic paraplegia, peripheral neuropathy, reduced vision, and brain changes like cerebellar atrophy, highlighting the need for more research
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Background: Galloway-Mowat syndrome (GAMOS) is a rare genetic disease characterized by early-onset nephrotic syndrome and microcephaly with central nervous system abnormalities. Pathogenic variants in genes encoding kinase, endopeptidase, and other proteins of small size (KEOPS) complex subunits cause GAMOS. The subunit (TP53RK binding protein) has been reported in only two patients with GAMOS with homozygous missense variants.

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A 56-year-old man was born to consanguineous parents. He experienced slow-progressing sensory disturbances in the upper extremities. T1-weighted images showed cerebellar atrophy.

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Hypomyelination of early myelinating structures (HEMS) has recently been defined as a new genetic disorder accompanied by clinical and MR imaging characteristics. However, no studies have focused on diffusion-weighted imaging (DWI) findings of HEMS. We would like to propose a "sheep sign," which is formed by DWI hyperintensity in the medial medullary lamina along with alternating high-low-high (HLH) intensity stripes in the posterior limb of the internal capsule.

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Article Synopsis
  • * In a case study of a Japanese girl with mosaic variegated aneuploidy syndrome, a known pathogenic variant was found using exome sequencing, but additional pathogenic variants were identified through RNA-seq and adaptive sampling techniques.
  • * The research demonstrated that RNA-seq can unveil transcriptomic abnormalities linked to pathological variants, showcasing the effectiveness of long-read sequencing in detecting complex genetic insertions.
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  • Congenital tracheal stenosis is a serious disorder caused by a narrow tracheal ring that lacks smooth muscle, but its genetic basis is not well understood.
  • Researchers conducted whole exome sequencing on a patient with this condition and found a new harmful variant in the TBX5 gene that affects protein stability and activity.
  • The study's findings, along with observations in mice, suggest that TBX5 variants play a significant role in the development of congenital tracheal stenosis.
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Background: Neurooculocardiogenitourinary syndrome (NOCGUS), a multisystemic syndrome characterized by motor disorder, intellectual disability, seizures, abnormal brain structure, ocular diseases, and cardiac diseases, has been reported with missense variant of WD repeat-containing protein 37 (WDR37) in humans. This report aimed to identify the cause of NOCGUS in an affected patient.

Case Presentation: We identified a de novo intronic 4-bp deletion of WDR37, c.

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Neurofibromatosis type 1 (NF1) is one of the most common hereditary neurocutaneous disorders. Here, we report a unique case of a patient with typical NF1 findings and infantile spasms who had three possibly pathogenic de novo variants, c.3586C>T, p.

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Sphingomyelin phosphodiesterase 4 (SMPD4) encodes a member of the Mg-dependent, neutral sphingomyelinase family that catalyzes the hydrolysis of the phosphodiester bond of sphingomyelin to form phosphorylcholine and ceramide. Recent studies have revealed that biallelic loss-of-function variants of SMPD4 cause syndromic neurodevelopmental disorders characterized by microcephaly, congenital arthrogryposis, and structural brain anomalies. In this study, three novel loss-of-function SMPD4 variants were identified using exome sequencing (ES) in two independent patients with developmental delays, microcephaly, seizures, and brain structural abnormalities.

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ATP1A2 encodes a subunit of sodium/potassium-transporting adenosine triphosphatase (Na /K -ATPase). Heterozygous pathogenic variants of ATP1A2 cause familial hemiplegic migraine, alternating hemiplegia of childhood, and developmental and epileptic encephalopathy. Biallelic loss-of-function variants in ATP1A2 lead to fetal akinesia, respiratory insufficiency, microcephaly, polymicrogyria, and dysmorphic facies, resulting in fetal death.

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Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophy. -related LCA accounts for 5-6% of LCA. We performed whole-exome sequencing and whole-genome sequencing (WGS) on 29 patients with clinically suspected LCA and examined ophthalmic findings in patients with biallelic pathogenic variants of .

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