End-stage ADPKD with a low-frequency PKD1 mosaic variant accelerated by chemoradiotherapy.

Autosomal dominant polycystic kidney disease (ADPKD) is commonly caused by PKD1, and mosaic PKD1 variants result in milder phenotypes. We present the case of a 32 year-old male with chronic active Epstein-Barr virus who underwent bone marrow transplantation with chemoradiotherapy at age 9. Despite a low-frequency mosaic splicing PKD1 variant, he developed severe renal cysts and end-stage renal disease in his 30 s. This case highlights how environmental factors may contribute to the genetic predisposition to ADPKD.

Genotype-Phenotype Correlation in WT1 Exon 8 to 9 Missense Variants.

INTRODUCTION: WT1 missense mutation in exon 8 or 9 causes infantile nephrotic syndrome with early progression to end-stage kidney disease (ESKD), Wilms tumor, and 46,XY female. However, some patients with missense mutations in exon 8 or 9 progress to ESKD in their teens or later. Therefore, we conducted a systematic review and functional analysis of WT1 transcriptional activity. METHODS: We conducted a systematic review of 174 cases with WT1 exon 8 or 9 missense variants from our cohort (n=13) and previous reports (n=161). Of these cases, mild and severe genotypes were selected for further in vitro functional analysis using luciferase assay. RESULTS: The median age of developing ESKD was 1.17 years. A comparative study was conducted among three WT1 genotype classes: mutations of the DNA-binding site (DBS group), mutations outside the DNA-binding site but at sites important for zinc finger structure formation by 2 cysteines and 2 histidines (C2H2 group), and mutations leading to other amino acid changes (Others group). The DBS group showed the severest phenotype and the C2H2 group was intermediate, whereas the Others group showed the mildest phenotype (developing ESKD at 0.90, 2.00, and 3.92 years, respectively, with significant differences). In vitro functional analysis showed dominant-negative effects for all variants; in addition, the DBS and C2H2 mutations were associated with significantly lower WT1 transcriptional activity than the other mutations. CONCLUSION: Not only the DNA-binding site but also C2H2 zinc finger structure sites are important for maintaining WT1 transcriptional activity, and their mutation causes severe clinical symptoms.

Prevalence of Wilson disease based on genome databases in Japan.

BACKGROUND: Wilson disease (WD) is an autosomal recessive disorder caused by mutations in the ATP7B gene. In 1984, Scheinberg and Sternlieb estimated the prevalence of WD to be 1:30 000. However, recent epidemiological studies have reported increasing prevalence rates in different populations. The carrier frequency of ATP7B variants and the prevalence of WD in the Japanese population have not been reported using multiple databases. METHODS: Multiple public databases were used. First, we included mutations in the ATP7B gene that were registered in the Human Gene Mutation Database (HGMD) Professional, where 885 ATP7B variants were identified as pathogenic. Next, we investigated the allele frequencies of these 885 variants in Japanese individuals using the Human Genetic Variation Database (HGVD) and the Japanese Multi Omics Reference Panel (jMorp). RESULTS: Of the 885 variants of ATP7B, 7 and 12 missense and nonsense variants, zero and three splicing variants, and zero and two small deletions were found in the HGVD and in jMorp, respectively. The total allele frequencies of the ATP7B mutations were 0.011 in the HGVD and 0.014 in the jMorp. According to these data, the carrier frequencies were 0.022 (2.2%) and 0.028 (2.8%), respectively, and patient frequencies were 0.000121 (1.21/10 000 individuals) and 0.000196 (1.96/10 000 individuals), respectively. CONCLUSIONS: This is the first study to report the carrier frequency of ATP7B variants and the prevalence of WD in Japan using multiple databases. The calculated prevalence of WD was comparatively higher than that of previous reports, indicating previous underdiagnosis or the existence of less severe phenotypes.

Elevated cytokine, chemokine, and growth and differentiation factor-15 levels in hemorrhagic shock and encephalopathy syndrome: A retrospective observational study.

Patients with hemorrhagic shock and encephalopathy syndrome (HSES) have a high early mortality rate, which may be caused by a 'cytokine storm'. However, there is little information on how cytokines and chemokines change over time in these patients. We aimed to describe the characteristics of HSES by examining changes in serum biomarker levels over time. Six patients with HSES were included. We retrospectively evaluated their clinical course and imaging/laboratory data. We measured serum levels of multiple cytokines [interleukin 1ß (IL-1ß), IL-2, IL-4, IL-6, IL-10, IL-17, interferon-gamma, and tumor necrosis factor alpha], chemokines (IL-8, monocyte chemoattractant protein-1, interferon-inducible protein-10), and growth and differentiation factor (GDF)-15. The highest cytokine and chemokine levels were noted in the first 24 h, and decreased thereafter. The GDF-15 level was markedly high. Cytokine, chemokine, and GDF-15 levels were significantly higher in patients with HSES than in controls in the first 24 h, except for IL-2 and IL-4. Patients with HSES have high inflammatory cytokine and chemokine levels, a high GDF-15 level in the first 24 h, and high lactate levels. Our study provides new insights on the pathophysiology of HSES, a detailed clinical picture of patients with HSES, and potential biomarkers.

Acute rhabdomyolysis following viral infection with coxsackie A4 in a 50-day-old infant with Fukuyama congenital muscular dystrophy.

BACKGROUND: Fukuyama congenital muscular dystrophy (FCMD), which is characterized by generalized muscle weakness, hypotonia, and motor delay during early infancy, gradually progresses with advanced age. Although acute rhabdomyolysis following infection in patients with FCMD has occasionally been reported, no studies have investigated rhabdomyolysis following viral infection in FCMD patients during early infancy. CASE REPORT: We report the case of a 50-day-old girl with no apparent symptoms of muscular dystrophy who developed severe acute rhabdomyolysis caused by viral infection, resulting in quadriplegia and respiratory failure therefore requiring mechanical ventilation. Brain magnetic resonance imaging incidentally showed the typical characteristics of FCMD, and FCMD was confirmed by genetic analysis, which revealed a 3-kb retrotransposon insertion in one allele of the fukutin gene and a deep intronic splicing variant in intron 5 in another allele. The virus etiology was confirmed to be Coxsackie A4. CONCLUSION: We report a severe case of acute rhabdomyolysis with the earliest onset of symptoms due to the Coxsackie A4 virus in a patient with FCMD. The present findings indicate that physicians should consider FCMD with viral infection a differential diagnosis if the patient presents with acute rhabdomyolysis following a fever.

A case of probable Vogt-Koyanagi-Harada disease in a 3-year-old girl.

BACKGROUND: Vogt-Koyanagi-Harada (VKH) disease is a T-cell-mediated autoimmune disorder characterized by bilateral granulomatous panuveitis with various systemic manifestations. Although VKH disease rarely occurs in the pediatric population, the clinical course tends to be aggressive, and the visual prognosis is worse than that in adult patients due to severe ocular complications secondary to recurrent inflammation. CASE PRESENTATION: A 3-year-old girl with probable VKH was referred to Kobe University Hospital. She had severe bilateral panuveitis with posterior synechiae of the iris, marked optic disk swelling, and serous retinal detachment in both eyes, and her best corrected visual acuities (BCVAs) were 20/200 OD and 20/125 OS. A third course of therapy was administered because serous retinal detachment remained after two courses of therapy. She was treated with three courses of high-dose intravenous corticosteroid therapy, followed by slow tapering of oral corticosteroids. Her BCVAs recovered to 20/16 OU, and relapse of ocular inflammation and side effect of treatment were not observed during the 1.5-year follow-up period. CONCLUSIONS: We experienced a pediatric patient with probable VKH disease who was treated with three courses of high-dose intravenous corticosteroid therapy. With the favorable clinical course in our patient, initial treatment with repeated high-dose intravenous corticosteroid therapy might be beneficial in pediatric VKH disease.

Fibrocartilaginous Embolism of the Spinal Cord in Children: A Case Report and Review of Literature.

Fibrocartilaginous embolism is assumed to be caused by fibrocartilaginous nucleus pulposus component migration through retrograde embolization to the spinal cord artery. Fibrocartilaginous embolism is currently not well recognized among pediatricians because of its rarity. We describe a previously healthy 15-year-old soccer player who, after kicking a ball, developed progressive weakness in both legs and urinary retention the next day. Magnetic resonance imaging revealed T2 hyperintensity in the anterior horn of the spinal cord at the Th12/L1 level with Schmorl node at the level of L1/2. We also review the previous literature on fibrocartilaginous embolism of the spinal cord in children (less than18 years age); a total of 25 pediatric patients, including our patient, were identified. The median age was 14 years, and 64% of the reviewed patients were female. The most common trigger event was intense exercise or sports. The neurological symptoms started within one day in most cases, and the time to symptom peak varied from a few hours to two weeks. The most common initial neurological symptoms were weakness or plegia (100%), followed by paresthesia or numbness (48%). Affected areas of the spinal cord were distributed evenly from the cervical to thoracolumbar regions. Although steroids and anticoagulants were most commonly used, the prognosis was quite poor (mild to severe sequelae with three deaths). Although fibrocartilaginous embolism is a very rare condition, physicians should be aware of the characteristics and include fibrocartilaginous embolism of the spinal cord in their differential diagnosis, especially for physically active patients.

Isolation and Characterization of Human Umbilical Cord-derived Mesenchymal Stem Cells from Preterm and Term Infants.

Mesenchymal stem cells (MSCs) have considerable therapeutic potential and attract increasing interest in the biomedical field. MSCs are originally isolated and characterized from bone marrow (BM), then acquired from tissues including adipose tissue, synovium, skin, dental pulp, and fetal appendages such as placenta, umbilical cord blood (UCB), and umbilical cord (UC). MSCs are a heterogeneous cell population with the capacity for (1) adherence to plastic in standard culture conditions, (2) surface marker expression of CD73+/CD90+/CD105+/CD45-/CD34-/CD14-/CD19-/HLA-DR- phenotypes, and (3) trilineage differentiation into adipocytes, osteocytes, and chondrocytes, as currently defined by the International Society for Cellular Therapy (ISCT). Although BM is the most widely used source of MSCs, the invasive nature of BM aspiration ethically limits its accessibility. Proliferation and differentiation capacity of MSCs obtained from BM generally decline with the age of the donor. In contrast, fetal MSCs obtained from UC have advantages such as vigorous proliferation and differentiation capacity. There is no ethical concern for UC sampling, as it is typically regarded as medical waste. Human UC starts to develop with continuing growth of the amniotic cavity at 4-8 weeks of gestation and keeps growing until reaching 50-60 cm in length, and it can be isolated during the whole newborn delivery period. To gain insight into the pathophysiology of intractable diseases, we have used UC-derived MSCs (UC-MSCs) from infants delivered at various gestational ages. In this protocol, we describe the isolation and characterization of UC-MSCs from fetuses/infants at 19-40 weeks of gestation.

Congenital chloride diarrhea needs to be distinguished from Bartter and Gitelman syndrome.

Pseudo-Bartter/Gitelman syndrome (p-BS/GS) encompasses a clinically heterogeneous group of inherited or acquired disorders similar to Bartter syndrome (BS) or Gitelman syndrome (GS), both renal salt-losing tubulopathies. Phenotypic overlap frequently occurs between p-BS/GS and BS/GS, which are difficult to diagnose based on their clinical presentation and require genetic tests for accurate diagnosis. In addition, p-BS/GS can occur as a result of other inherited diseases such as cystic fibrosis, autosomal dominant hypocalcemia, Dent disease, or congenital chloride diarrhea (CCD). However, the detection of the variants in genes other than known BS/GS-causing genes by conventional Sanger sequencing requires substantial time and resources. We studied 27 cases clinically diagnosed with BS/GS, but with negative genetic tests for known BS/GS genes. We conducted targeted sequencing for 22 genes including genes responsible for tubulopathies and other inherited diseases manifesting with p-BS/GS symptoms. We detected the SLC26A3 gene variants responsible for CCD in two patients. In Patient 1, we found the SLC26A3 compound heterozygous variants: c.354delC and c.1008insT. In Patient 2, we identified the compound heterozygous variants: c.877G > A, p.(Glu293Lys), and c.1008insT. Our results suggest that a comprehensive genetic screening system using targeted sequencing is useful for the diagnosis of patients with p-BS/GS with alternative genetic origins.

De novo variants in RHOBTB2, an atypical Rho GTPase gene, cause epileptic encephalopathy.

By whole exome sequencing, we identified three de novo RHOBTB2 variants in three patients with epileptic encephalopathies (EEs). Interestingly, all three patients showed acute encephalopathy (febrile status epilepticus), with magnetic resonance imaging revealing hemisphere swelling or reduced diffusion in various brain regions. RHOBTB2 encodes Rho-related BTB domain-containing protein 2, an atypical Rho GTPase that is a substrate-specific adaptor or itself is a substrate for the Cullin-3 (CUL3)-based ubiquitin ligase complex. Transient expression experiments in Neuro-2a cells revealed that mutant RHOBTB2 was more abundant than wild-type RHOBTB2. Coexpression of CUL3 with RHOBTB2 decreased the level of wild-type RHOBTB2 but not the level of any of the three mutants, indicating impaired CUL3 complex-dependent degradation of the three mutants. These data indicate that RHOBTB2 variants are a rare genetic cause of EEs, in which acute encephalopathy might be a characteristic feature, and that precise regulation of RHOBTB2 levels is essential for normal brain function.

Development of ultra-deep targeted RNA sequencing for analyzing X-chromosome inactivation in female Dent disease.

The pattern of X-chromosome inactivation (XCI) can affect the clinical severity of X-linked disorders in females. XCI pattern analysis has been conducted mainly by HUMARA assay, a polymerase chain reaction-based assay using a methylation-sensitive restriction enzyme. However, this assay examines the XCI ratio of the androgen receptor gene at the genomic DNA level and does not reflect the ratio of either targeted gene directly or at the mRNA level. Here, we report four females with Dent disease, and we clarified the correlation between XCI and female cases of Dent disease using not only HUMARA assay but also a novel analytical method by RNA sequencing. We constructed genetic analysis for 4 female cases showing high level of urinary low-molecular-weight proteinuria and their parents. Their XCI pattern was analyzed by both HUMARA assay and an ultra-deep targeted RNA sequencing of the CLCN5 gene using genomic DNA and mRNA extracted from both leukocytes and urine sediment. All four cases possessed pathogenic variants of the CLCN5 gene. XCI analysis revealed skewed XCI in only two cases, while the other two showed random XCI. All assay results of HUMARA and targeted RNA sequencing in both leukocytes and urinary sediment were clearly identical in all four cases. We developed a novel XCI analytical assay of ultra-deep targeted RNA sequencing and revealed that skewed XCI explains the mechanism of onset of female Dent disease in only half of such cases.

Clinically Mild Encephalitis/Encephalopathy With a Reversible Splenial Lesion Accompanied by Epstein-Barr Virus Hemophagocytic Lymphohistiocytosis: A Case Report and Review of the Literature.

Central nervous system involvement in hemophagocytic lymphohistiocytosis (HLH) is associated with a poor outcome. For such patients, it is unknown whether more aggressive therapies, such as intrathecal methotrexate or hydrocortisone, are inevitably required. We present a very rare case of 3-year-old Japanese girl who developed mild encephalitis/encephalopathy with a reversible splenial lesion, accompanied by Epstein-Barr virus-associated HLH, and review previous similar reports. Our case and previous reports suggest that mild encephalitis/encephalopathy with a reversible splenial lesion accompanied by Epstein-Barr virus-associated HLH has a relatively good prognosis, even in the absence of intrathecal treatments.