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Hibino S, Morisada N, Takeda A, Tanaka K, Nozu K, Yamakawa S, Iijima K, Fujita N. Medullary Cystic Kidney Disease and Focal Segmental Glomerulosclerosis Caused by a Compound Heterozygous Mutation in TTC21B. Intern Med 2020; 59:1735-1738. [PMID: 32238723 PMCID: PMC7434538 DOI: 10.2169/internalmedicine.4266-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mutations in the TTC21B gene have been identified in patients with nephronophthisis and were recently found in some patients with focal segmental glomerulosclerosis. We herein report a Japanese boy with end-stage renal disease due to medullary polycystic kidney disease and primary focal segmental glomerulosclerosis. Next-generation sequencing detected a new compound heterozygous missense mutation in the TTC21B gene. His renal pathological findings and gene mutations have not been previously reported in patients with ciliopathy. For children with severe renal dysfunction, mutations in the TTC21B gene cause both ciliopathy characterized by bilateral polycystic kidney disease and primary focal segmental glomerulosclerosis.
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Aoto Y, Kise T, Nakanishi K, Nagano C, Horinouchi T, Yamamura T, Ishiko S, Sakakibara N, Shima Y, Morisada N, Iijima K, Nozu K. A case with somatic and germline mosaicism in COL4A5 detected by multiplex ligation-dependent probe amplification in X-linked Alport syndrome. CEN Case Rep 2020; 9:431-436. [PMID: 32621070 DOI: 10.1007/s13730-020-00503-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 06/28/2020] [Indexed: 01/19/2023] Open
Abstract
X-linked Alport syndrome (XLAS) is a progressive hereditary kidney disease caused by mutations in the COL4A5 gene encoding the type IV collagen α5 chain. To date, 11 cases having somatic mosaic variants in COL4A5 have been reported; however, all of them involved single-nucleotide variations (SNVs). Here, we report a female XLAS patient with somatic mosaicism identified by copy number variation (CNV) in COL4A5. The case was a 35-year-old female, the mother of the proband, whose only clinical symptom was hematuria. The proband, who was the son of this patient, was diagnosed with XLAS by gene testing, which showed a large hemizygous deletion from exon 3-51 in COL4A5 detected by next-generation sequencing and then confirmed by multiplex ligation-dependent probe amplification (MLPA). Then, MLPA analysis revealed that the female patient had the same deletion with only a 20% copy number reduction compared with a normal female control; she was thus diagnosed with XLAS with somatic mosaicism. CNVs in COL4A5 are relatively rare and, to the best of our knowledge, somatic mosaic variants with CNVs have never been reported. This case clearly featured a germline variant because the patient's son exhibited XLAS. This is thus the first case report on an XLAS patient having CNV in COL4A5 with somatic mosaicism. The obtained findings were very important for the genetic counseling of this family.
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Araki Y, Kawaguchi A, Sakakibara N, Nagaoka Y, Yamamura T, Horinouchi T, Nagano C, Morisada N, Iijima K, Nozu K. Poststreptococcal acute glomerulonephritis can be a risk factor for accelerating kidney dysfunction in Alport syndrome: a case experience. CEN Case Rep 2020; 9:418-422. [PMID: 32592137 DOI: 10.1007/s13730-020-00498-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/17/2020] [Indexed: 11/30/2022] Open
Abstract
Alport syndrome (AS) is a progressive kidney disease. Male cases with X-linked AS (XLAS) are reported to develop end-stage kidney disease (ESKD) at the age of around 20-30 years. One risk factor for developing ESKD at a young age is a genotype of having truncating variants in the COL4A5 gene. However, to date, other such factors have remained unclear. Here, we describe a 15-year-old Japanese boy with XLAS who had a missense variant in the COL4A5 gene. He presented with gross hematuria, severe proteinuria, oliguria, systemic edema, body weight gain, and hypertension after pharyngitis. Blood examination showed kidney dysfunction, hypocomplementemia, and elevated antistreptolysin-O level. We diagnosed him with poststreptococcal acute glomerulonephritis (PSAGN) and he was stopped treatment by lisinopril, and received supportive treatment. However, he showed an unusual clinical course for PSAGN and, consequently, developed ESKD 15 months after the onset of PSAGN without recovery from the kidney dysfunction. This case showed that the onset of PSAGN can be a risk factor for AS patients to develop ESKD at a young age.
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Horinouchi T, Yamamura T, Minamikawa S, Nagano C, Sakakibara N, Nakanishi K, Shima Y, Morisada N, Ishiko S, Aoto Y, Nagase H, Takeda H, Rossanti R, Ishimori S, Kaito H, Matsuo M, Iijima K, Nozu K. Pathogenic evaluation of synonymous COL4A5 variants in X-linked Alport syndrome using a minigene assay. Mol Genet Genomic Med 2020; 8:e1342. [PMID: 32543079 PMCID: PMC7434753 DOI: 10.1002/mgg3.1342] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/13/2020] [Accepted: 05/19/2020] [Indexed: 12/20/2022] Open
Abstract
Background X‐linked Alport syndrome (XLAS) is a progressive, hereditary glomerular nephritis of variable severity caused by pathogenic COL4A5 variants. Currently, genetic testing is widely used for diagnosing XLAS; however, determining the pathogenicity of variants detected by such analyses can be difficult. Intronic variants or synonymous variants may cause inherited diseases by inducing aberrant splicing. Transcript analysis is necessary to confirm the pathogenicity of such variants, but it is sometimes difficult to extract mRNA directly from patient specimens. Methods In this study, we conducted in vitro splicing analysis using a hybrid minigene assay and specimens from three XLAS patients with synonymous variants causing aberrant splicing, including previously reported pathogenic mutations in the same codon. The variants were c.876 A>T (p.Gly292=), c.2358 A>G (p.Pro786=), and c.3906 A>G (p.Gln1302=). Results The results from our hybrid minigene assay were sufficient to predict splicing abnormalities; c.876 A>T cause 17‐bp del and 35‐bp del, c.2358 A>G cause exon 29 skipping, c.3906 A>G cause exon 42 skipping, which are very likely to cause pathogenicity. Further, patients carrying c.2358 A>G exhibited a mild phenotype that may have been associated with the presence of both normal and abnormally spliced transcripts. Conclusion The minigene system was shown to be a sensitive assay and a useful tool for investigating the pathogenicity of synonymous variants.
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Jia X, Yamamura T, Gbadegesin R, McNulty MT, Song K, Nagano C, Hitomi Y, Lee D, Aiba Y, Khor SS, Ueno K, Kawai Y, Nagasaki M, Noiri E, Horinouchi T, Kaito H, Hamada R, Okamoto T, Kamei K, Kaku Y, Fujimaru R, Tanaka R, Shima Y, Baek J, Kang HG, Ha IS, Han KH, Yang EM, Abeyagunawardena A, Lane B, Chryst-Stangl M, Esezobor C, Solarin A, Dossier C, Deschênes G, Vivarelli M, Debiec H, Ishikura K, Matsuo M, Nozu K, Ronco P, Cheong HI, Sampson MG, Tokunaga K, Iijima K. Common risk variants in NPHS1 and TNFSF15 are associated with childhood steroid-sensitive nephrotic syndrome. Kidney Int 2020; 98:1308-1322. [PMID: 32554042 DOI: 10.1016/j.kint.2020.05.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 04/23/2020] [Accepted: 05/01/2020] [Indexed: 12/16/2022]
Abstract
To understand the genetics of steroid-sensitive nephrotic syndrome (SSNS), we conducted a genome-wide association study in 987 childhood SSNS patients and 3,206 healthy controls with Japanese ancestry. Beyond known associations in the HLA-DR/DQ region, common variants in NPHS1-KIRREL2 (rs56117924, P=4.94E-20, odds ratio (OR) =1.90) and TNFSF15 (rs6478109, P=2.54E-8, OR=0.72) regions achieved genome-wide significance and were replicated in Korean, South Asian and African populations. Trans-ethnic meta-analyses including Japanese, Korean, South Asian, African, European, Hispanic and Maghrebian populations confirmed the significant associations of variants in NPHS1-KIRREL2 (Pmeta=6.71E-28, OR=1.88) and TNFSF15 (Pmeta=5.40E-11, OR=1.33) loci. Analysis of the NPHS1 risk alleles with glomerular NPHS1 mRNA expression from the same person revealed allele specific expression with significantly lower expression of the transcript derived from the risk haplotype (Wilcox test p=9.3E-4). Because rare pathogenic variants in NPHS1 cause congenital nephrotic syndrome of the Finnish type (CNSF), the present study provides further evidence that variation along the allele frequency spectrum in the same gene can cause or contribute to both a rare monogenic disease (CNSF) and a more complex, polygenic disease (SSNS).
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Yamamura T, Horinouchi T, Adachi T, Terakawa M, Takaoka Y, Omachi K, Takasato M, Takaishi K, Shoji T, Onishi Y, Kanazawa Y, Koizumi M, Tomono Y, Sugano A, Shono A, Minamikawa S, Nagano C, Sakakibara N, Ishiko S, Aoto Y, Kamura M, Harita Y, Miura K, Kanda S, Morisada N, Rossanti R, Ye MJ, Nozu Y, Matsuo M, Kai H, Iijima K, Nozu K. Development of an exon skipping therapy for X-linked Alport syndrome with truncating variants in COL4A5. Nat Commun 2020; 11:2777. [PMID: 32488001 PMCID: PMC7265383 DOI: 10.1038/s41467-020-16605-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 05/12/2020] [Indexed: 11/10/2022] Open
Abstract
Currently, there are no treatments for Alport syndrome, which is the second most commonly inherited kidney disease. Here we report the development of an exon-skipping therapy using an antisense-oligonucleotide (ASO) for severe male X-linked Alport syndrome (XLAS). We targeted truncating variants in exon 21 of the COL4A5 gene and conducted a type IV collagen α3/α4/α5 chain triple helix formation assay, and in vitro and in vivo treatment efficacy evaluation. We show that exon skipping enabled trimer formation, leading to remarkable clinical and pathological improvements including expression of the α5 chain on glomerular and the tubular basement membrane. In addition, the survival period was clearly prolonged in the ASO treated mice group. This data suggests that exon skipping may represent a promising therapeutic approach for treating severe male XLAS cases. Alport syndrome is a progressive inherited nephritis accompanied by sensorineural loss of hearing and ocular abnormalities, for which there is currently no effective therapy. Here, the authors develop an exon-skipping therapy using an antisense-oligonucleotide and show it is effective in mouse models.
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Komatsu M, Yamamoto N, Kawamoto T, Kawakami Y, Hara H, Uemura S, Nishimura N, Akisue T, Kuroda R, Iijima K, Jimbo N, Kanzawa M, Kajimoto K, Itoh T, Hirose T. Soft tissue tumor with novel NR1D1-MAML1 fusion in a pediatric case. Virchows Arch 2020; 477:891-895. [PMID: 32474730 DOI: 10.1007/s00428-020-02838-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/26/2020] [Accepted: 05/03/2020] [Indexed: 01/12/2023]
Abstract
We herein describe soft tissue tumor arising in the lower extremity of a pediatric patient. The tumor displayed a unique and wide range of histological features, sheet-like and cohesive growth pattern consisting of enlarged round to epithelioid atypical cells with a large alveolar and pseudopapillary histological architecture, focally mimicking alveolar soft part sarcoma and MiT family translocation renal cell carcinoma. Tumor cells were focally immunoreactive for cytokeratin, S-100, and EMA. RNA sequencing identified a novel in-frame NR1D1 (exon 5)-MAML1 (exon 2) gene rearrangement resulting in the formation of a putative chimeric protein containing the N-terminal C4-type zing finger domains of NR1D1 and the C-terminal MAML1 protein, which was confirmed by subsequent RT-PCR, Sanger sequencing, and FISH assay. To the best of our knowledge, NR1D1-MAML1 fusion has not yet been described in any neoplasms, suggesting the emergence of a novel tumor entity.
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Bo R, Musha I, Yamada K, Kobayashi H, Hasegawa Y, Awano H, Arao M, Kikuchi T, Taketani T, Ohtake A, Yamaguchi S, Iijima K. Need for strict clinical management of patients with carnitine palmitoyltransferase II deficiency: Experience with two cases detected by expanded newborn screening. Mol Genet Metab Rep 2020; 24:100611. [PMID: 32489884 PMCID: PMC7260588 DOI: 10.1016/j.ymgmr.2020.100611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/31/2022] Open
Abstract
In Japan, carnitine palmitoyltransferase II (CPTII) deficiency has been included as one of the primary target diseases in the expanded newborn mass screening program since 2018. However, many cases of the severe infantile hepatocardiomuscular form of CPTII deficiency showed severe neurodevelopmental delay or sudden death, which indicated that management of CPTII deficiency in the acute phase remains to be studied in detail. Herein, we discuss two cases diagnosed by newborn mass screening. Patient 1 was under strict clinical management from the neonatal period, with >20 admissions in 14 months, while Patient 2 was managed using a relatively relaxed approach, with only 2 admissions in the same period. Patient 1 showed normal development; however, Patient 2 expired at the age of 1 year 2 months. To develop strategies for preventing sudden deaths in patients with CPTII deficiency, this retrospective study focused on detailed clinical management practices and biochemical findings during the acute phase. We also investigated the correlation between conventional biomarkers (such as creatine kinase) and long-chain acylcarnitines. We propose that strict monitoring and immediate medical attention, even in case of slight fever or minor abdominal symptoms, can help prevent sudden death in patients with CPTII deficiency. Considering the higher morbidity rate of such patients, strict and acute management of CPTII deficiency cannot be overemphasized.
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Ishida Y, Nishiyama M, Yamaguchi H, Tomioka K, Tanaka T, Takeda H, Tokumoto S, Toyoshima D, Maruyama A, Seino Y, Aoki K, Nozu K, Nishimura N, Kurosawa H, Iijima K, Nagase H. Thiamylal anaesthetic therapy for febrile refractory status epilepticus in children. Seizure 2020; 80:12-17. [PMID: 32480278 DOI: 10.1016/j.seizure.2020.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 12/25/2019] [Accepted: 03/23/2020] [Indexed: 10/24/2022] Open
Abstract
PURPOSE To evaluate barbiturate anaesthetic therapy using thiamylal for febrile refractory status epilepticus (fRSE) in children. METHODS This was a review of a prospectively-collected database between April 2012-March 2016 for fRSE cases treated with thiamylal anaesthetic therapy in a single paediatric hospital in Japan. The sample comprised 23 children (median age, 23 months) with fRSE that underwent thiamylal anaesthetic therapy for convulsive seizures lasting longer than 60 min, sustained after intravenous administration of benzodiazepine and non-benzodiazepine anticonvulsants. The intervention comprised protocol-based thiamylal anaesthetic therapy with bolus administration. We measured the dose and time required to achieve the burst suppression pattern (BSP) on electroencephalography, seizure recurrence, death, neurological sequelae, and complications. RESULTS All patients except one reached the BSP. The thiamylal median dose until reaching the BSP was 27.5 mg/kg, and the median time from thiamylal administration to reaching the BSP was 109.5 min. There was one case of immediate treatment failure and one of withdrawal seizure, but no breakthrough seizure. No deaths occurred during treatment, and neurological sequelae occurred in four cases (17%). Vasopressors were administered in all cases. Other complications included 11 cases of pneumonia and one of enterocolitis. CONCLUSION We revealed the time and dose required to reach the BSP with thiamylal anaesthetic therapy using bolus administration in children. Our results suggested that reaching the BSP with bolus administration requires markedly less time than without bolus administration, rarely causes seizure recurrence in paediatric fRSE, and causes haemodynamic dysfunction and infections as often as observed without bolus administration.
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Uemura S, Mori T, Ishiko S, Takafuji S, Nino N, Yamamoto N, Hayakawa A, Nishimura N, Hara H, Kawamoto T, Akisue T, Iijima K. Retrospective analysis of high-dose chemotherapy followed by autologous stem cell transplantation for high-risk pediatric osteosarcoma. Pediatr Hematol Oncol 2020; 37:337-343. [PMID: 32151185 DOI: 10.1080/08880018.2020.1729906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The outcomes of osteosarcoma with poor prognostic factors, such as poor responders, metastatic disease at diagnosis, and relapsed or refractory disease, are poor. We reviewed the clinical records of the patients diagnosed with osteosarcoma at our institute between 2004 and 2018 who received high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) in our institute. Ten patients of osteosarcoma with poor responder, refractory status, and metastatic disease at diagnosis received high-dose chemotherapy followed by ASCT. Four patients underwent high-dose chemotherapy followed by ASCT with the conditioning regimen consisted of thiotepa and melphalan (MEL). Five patients underwent high-dose chemotherapy followed by ASCT with the conditioning regimen consisted of intravenous busulfan (BU) and MEL. One patient underwent tandem high-dose chemotherapy followed by ASCT with BU and MEL followed by carboplatin and etoposide. None of the ten patients died of regimen related toxicities. None of the five patients with poor responders who underwent high-dose chemotherapy followed by ASCT as part of consolidation therapy died of disease after ASCT. High-dose chemotherapy followed by ASCT might be effective for poor responders in osteosarcoma.
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Miyauchi H, Fujioka K, Okubo S, Nishida K, Ashina M, Ikuta T, Okata Y, Maeda K, Iijima K, Bitoh Y. Insulin therapy for hyperglycemia in neonatal sepsis using a preterm mouse model. Pediatr Int 2020; 62:581-586. [PMID: 31885143 DOI: 10.1111/ped.14126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 11/21/2019] [Accepted: 12/25/2019] [Indexed: 11/29/2022]
Abstract
BACKGROUND Stress-induced hyperglycemia is a frequent complication of neonatal sepsis. Hyperglycemia induces oxidative stress and immunosuppression. We investigated the glucose kinetics and effect of insulin administration during stress-induced hyperglycemia in a neonatal sepsis mouse model. METHODS A stock cecal slurry (CS) solution was prepared from adult cecums and 3.0 mg of CS/g (LD40 ) was administered intraperitoneally to 4-day-old FVB mouse pups. Blood glucose levels were measured at 1.5, 3, 6, and 9 h post-sepsis induction and compared with basal levels. Two different doses of ultrafast-acting insulin were administered subcutaneously, and blood glucose levels and survival rates were monitored. RESULTS Blood glucose levels were significantly higher than those of baseline levels with a peak at 3 h, which progressively decreased from 6 to 9 h post-sepsis induction. Insulin treatment reduced post-sepsis-induced hyperglycemia at 1.5 and 3 h. The mortality rate of CS-only pups (39%) was similar to that of CS + 1 U/kg insulin pups (60%). However, the mortality rate of CS + 5 U/kg insulin pups (82%) was significantly higher than that of CS-only pups. CONCLUSIONS Marked hyperglycemia was induced immediately after post-sepsis induction, and the high-dose insulin treatment increased mortality post-induction. Stress-induced hyperglycemia could therefore be a physiological and protective response for preterm sepsis, and aggressive treatment of this hyperglycemia might be contraindicated.
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Morisada N, Hamada R, Miura K, Ye MJ, Nozu K, Hattori M, Iijima K. Bardet-Biedl syndrome in two unrelated patients with identical compound heterozygous SCLT1 mutations. CEN Case Rep 2020; 9:260-265. [PMID: 32253632 DOI: 10.1007/s13730-020-00472-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 03/29/2020] [Indexed: 12/23/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a rare autosomal recessive ciliopathy characterized by retinitis pigmentosa (RP), truncal obesity, cognitive impairment, hypogonadism in men, polydactyly, and renal abnormalities with severe renal dysfunction. Twenty-two causative genes have already been reported for this disorder. In this study, we identified two unrelated Japanese patients with clinical diagnoses of BBS associated with compound heterozygous SCLT1 mutation. Patient 1 was a 10-year-old girl, and patient 2 was a 22-year-old man. Both the patients showed severe renal dysfunction in childhood, RP, mild intellectual disability, short stature, and truncal obesity, without oral aberrations and polydactyly. Patient 2 also had hypogonadism. We identified two missense variants in SCLT1, c.[1218G > A] and [1631A > G], in both the patients by next-generation sequencing. Subsequent cDNA analysis revealed that c.1218G > A affected exon 14 skipping in SCLT1. To date, SCLT1 has been reported as the causative gene of oral-facial-digital syndrome type IX, and Senior-Løken syndrome. The phenotypes of both the present patients were compatible with BBS. These results highlight SCLT1 as an additional candidate for BBS phenotype in an autosomal recessive manner.
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Nozu K, Yamamura T, Horinouchi T, Nagano C, Sakakibara N, Ishikura K, Hamada R, Morisada N, Iijima K. Inherited salt-losing tubulopathy: An old condition but a new category of tubulopathy. Pediatr Int 2020; 62:428-437. [PMID: 31830341 DOI: 10.1111/ped.14089] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/11/2019] [Accepted: 10/21/2019] [Indexed: 12/16/2022]
Abstract
Bartter syndrome (BS) and Gitelman syndrome (GS) are syndromes associated with congenital tubular dysfunction, characterized by hypokalemia and metabolic alkalosis. Clinically, BS is classified into two types: the severe antenatal/neonatal type, which develops during the fetal period with polyhydramnios and preterm delivery; and the relatively mild classic type, which is usually found during infancy with failure to thrive. GS can be clinically differentiated from BS by its age at onset, usually after school age, or laboratory findings of hypomagnesemia and hypocalciuria. Recent advances in molecular biology have shown that these diseases can be genetically classified into type 1 to 5 BS and GS. As a result, it has become clear that the clinical classification of antenatal/neonatal BS, classic BS, and GS does not always correspond to the clinical symptoms associated with the genotypes in a one-to-one manner; and there is clinically no clear differential border between type 3 BS and GS. This has caused confusion among clinicians in the diagnosis of these diseases. It has been proposed that the disease name "inherited salt-losing tubulopathy" can be used for cases of tubulopathies accompanied by hypokalemia and metabolic alkalosis. It is reasonable to use this term prior to genetic typing into type 1-5 BS or GS, to avoid confusion in a clinical setting. In this article, we review causative genes and phenotypic correlations, diagnosis, and treatment strategies for salt-losing tubulopathy as well as the clinical characteristics of pseudo-BS/GS, which can also be called a "salt-losing disorder".
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Inoue T, Nagano C, Matsuo M, Yamamura T, Sakakibara N, Horinouchi T, Shibagaki Y, Ichikawa D, Aoto Y, Ishiko S, Ishimori S, Rossanti R, Iijima K, Nozu K. Functional analysis of suspected splicing variants in CLCN5 gene in Dent disease 1. Clin Exp Nephrol 2020; 24:606-612. [PMID: 32201916 PMCID: PMC7935734 DOI: 10.1007/s10157-020-01876-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 03/06/2020] [Indexed: 02/07/2023]
Abstract
Background In recent years, the elucidation of splicing abnormalities as a cause of hereditary diseases has progressed. However, there are no comprehensive reports of suspected splicing variants in the CLCN5 gene in Dent disease cases. We reproduced gene mutations by mutagenesis, inserted the mutated genes into minigene vectors, and investigated the pathogenicity and onset mechanisms of these variants. Methods We conducted functional splicing assays using a hybrid minigene for six suspected splicing variants (c.105G>A, c.105+5G>C, c.106−17T>G, c.393+4A>G, c.517−8A>G, c.517−3C>A) in CLCN5. We extracted information on these variants from the Human Gene Mutation Database. We reproduced minigene vectors with the insertion of relevant exons with suspected splicing variants. We then transfected these minigene vectors into cultured cells and extracted and analyzed the mRNA. In addition, we conducted in silico analysis to confirm our minigene assay results. Results We successfully determined that five of these six variants are pathogenic via the production of splicing abnormalities. One showed only normal transcript production and was thus suspected of not being pathogenic (c.106−17T>G). Conclusion We found that five CLCN5 variants disrupted the original splice site, resulting in aberrant splicing. It is sometimes difficult to obtain mRNA from patient samples because of the fragility of mRNA or its low expression level in peripheral leukocytes. Our in vitro system can be used as an alternative to in vivo assays to determine the pathogenicity of suspected splicing variants. Electronic supplementary material The online version of this article (10.1007/s10157-020-01876-x) contains supplementary material, which is available to authorized users.
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Watanabe Y, Fujinaga S, Sakuraya K, Morisada N, Nozu K, Iijima K. Rapidly Progressive Nephronophthisis in a 2-Year-Old Boy with a Homozygous SDCCAG8 Mutation. TOHOKU J EXP MED 2020; 249:29-32. [PMID: 31534065 DOI: 10.1620/tjem.249.29] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Nephronophthisis (NPHP) is an autosomal recessive cystic kidney disease that is characterized by primary ciliary dysfunction (ciliopathy) and progresses to end-stage kidney disease (ESKD) during the second decade of life (juvenile and adolescent NPHP) or before the age of 3 years (infantile NPHP). Here we describe the case of an infant with NPHP who carries a homozygous mutation in SDCCAG8 (also called NPHP10 or BBS16) that encodes SDCCAG8 (serologically defined colon cancer antigen 8). SDCCAG8 is localized at the centrioles of both renal epithelial cells and retinal photoreceptor cells. A mutation in SDCCAG8 is also associated with Bardet-Biedl syndrome (BBS), characterized by NPHP, obesity, polydactyly, and rod-cone dystrophy. A 2-year-old boy was referred to our hospital due to kidney dysfunction of unknown etiology; the patient presented with delayed development and opsoclonus but did not exhibit the clinical characteristics of BBS. Histological findings such as dilatation of tubules and irregular thickness of tubular basement membrane confirmed the diagnosis of NPHP. Four months after referral, the patient's renal function was rapidly deteriorated, and emergency peritoneal dialysis was initiated. Next-generation sequencing (NGS) was performed, showing that the patient carries a homozygous four-base-pair deletion in SDCCAG8 (c.849_852delTTTG, p.Cys283Ter). The patient's parents were also found to be heterozygous for this loss-of-function mutation. To the best of our knowledge, the present patient is the first case of biopsy-proven infantile NPHP with a homozygous SDCCAG8 mutation. We conclude that NGS is extremely useful in the identification of SDCCAG8-related NPHP as a cause of sudden-onset ESKD during infancy.
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Yotani N, Nabetani M, Feudtner C, Honda J, Kizawa Y, Iijima K. Withholding and withdrawal of life-sustaining treatments for neonate in Japan: Are hospital practices associated with physicians' beliefs, practices, or perceived barriers? Early Hum Dev 2020; 141:104931. [PMID: 31810052 DOI: 10.1016/j.earlhumdev.2019.104931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To describe the current status of withholding or withdrawal of life-sustaining interventions (LSI) for neonates in Japan and to identify physician- and institutional-related factors that may affect advance care planning (ACP) practices with parents. STUDY DESIGN A self-reported questionnaire was administered to assess frequency of withholding and withdrawing intensive care at the respondent's facility, the physician's degree of affirming various beliefs about end-of-life care that was compared to 7 European countries, their self-reported ACP practices and perceived barriers to ACP. Three neonatologists at all 298 facilities accredited by the Japan Society for Neonatal Health and Development were surveyed, with 572 neonatologists at 217 facilities responding. RESULTS At 76% of facilities, withdrawing intensive care treatments was "never" done, while withholding intensive care had been done "sometimes" or more frequently at 82% of facilities. Japanese neonatologists differed from European neonatologists regarding their degree of affirmation of 3 out of 7 queried beliefs about end-of-life care. In hospitals that were more likely to "sometimes" (or more often) withdraw treatments, respondents were less likely to affirm beliefs about doing "everything possible" or providing the "maximum of intensive care". Self-reported ACP practices did not vary between neonatologists based on their hospital's overall pattern of withholding or withdrawing treatments. CONCLUSION Among NICU facilities in Japan, 21% had been sometimes withdrawing LSI and 82% had been "sometimes" withholding LSI. Institutional treatment practices may have a strong association with physicians' beliefs that then affect end-of-life discussions, but not with self-reported ACP practices.
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Thwin KK, Ishida T, Uemura S, Yamamoto N, Lin KS, Tamura A, Kozaki A, Saito A, Kishimoto K, Mori T, Hasegawa D, Kosaka Y, Nino N, Takafuji S, Iijima K, Nishimura N. Level of Seven Neuroblastoma-Associated mRNAs Detected by Droplet Digital PCR Is Associated with Tumor Relapse/Regrowth of High-Risk Neuroblastoma Patients. J Mol Diagn 2020; 22:236-246. [DOI: 10.1016/j.jmoldx.2019.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 07/25/2019] [Accepted: 10/17/2019] [Indexed: 02/07/2023] Open
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Yamaguchi H, Taniguchi-Ikeda M, Nagase H, Ito Y, Tokumoto S, Toyoshima D, Enkhjargal S, Nishiyama M, Awano H, Kurosawa H, Kasai M, Maruyama A, Iijima K. Acute rhabdomyolysis following viral infection with coxsackie A4 in a 50-day-old infant with Fukuyama congenital muscular dystrophy. J Infect Chemother 2020; 26:516-519. [PMID: 31983616 DOI: 10.1016/j.jiac.2019.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 11/07/2019] [Accepted: 12/21/2019] [Indexed: 10/25/2022]
Abstract
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.
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Minamikawa S, Miwa S, Inagaki T, Nishiyama K, Kaito H, Ninchoji T, Yamamura T, Nagano C, Sakakibara N, Ishimori S, Hara S, Yoshikawa N, Hirano D, Harada R, Hamada R, Matsunoshita N, Nagata M, Shima Y, Nakanishi K, Nagase H, Takeda H, Morisada N, Iijima K, Nozu K. Molecular mechanisms determining severity in patients with Pierson syndrome. J Hum Genet 2020; 65:355-362. [PMID: 31959872 DOI: 10.1038/s10038-019-0715-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 01/15/2023]
Abstract
Null variants in LAMB2 cause Pierson syndrome (PS), a severe congenital nephrotic syndrome with ocular and neurological defects. Patients' kidney specimens show complete negativity for laminin β2 expression on glomerular basement membrane (GBM). In contrast, missense variants outside the laminin N-terminal (LN) domain in LAMB2 lead to milder phenotypes. However, we experienced cases not showing these typical genotype-phenotype correlations. In this paper, we report six PS patients: four with mild phenotypes and two with severe phenotypes. We conducted molecular studies including protein expression and transcript analyses. The results revealed that three of the four cases with milder phenotypes had missense variants located outside the LN domain and one of the two severe PS cases had a homozygous missense variant located in the LN domain; these variant positions could explain their phenotypes. However, one mild case possessed a splicing site variant (c.3797 + 5G>A) that should be associated with a severe phenotype. Upon transcript analysis, this variant generated some differently sized transcripts, including completely normal transcript, which could have conferred the milder phenotype. In one severe case, we detected the single-nucleotide substitution of c.4616G>A located outside the LN domain, which should be associated with a milder phenotype. However, we detected aberrant splicing caused by the creation of a novel splice site by this single-base substitution. These are novel mechanisms leading to an atypical genotype-phenotype correlation. In addition, all four cases with milder phenotypes showed laminin β2 expression on GBM. We identified novel mechanisms leading to atypical genotype-phenotype correlation in PS.
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Yamaguchi H, Nishiyama M, Tokumoto S, Ishida Y, Tomioka K, Aoki K, Seino Y, Toyoshima D, Takeda H, Kurosawa H, Nozu K, Maruyama A, Tanaka R, Iijima K, Nagase H. Detailed characteristics of acute encephalopathy with biphasic seizures and late reduced diffusion: 18-year data of a single-center consecutive cohort. J Neurol Sci 2020; 411:116684. [PMID: 32001378 DOI: 10.1016/j.jns.2020.116684] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/10/2020] [Accepted: 01/13/2020] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a syndrome characterized by biphasic seizures with impaired consciousness. AESD is rare outside Asia, and consecutive cohort studies are therefore scarce. Herein, we aimed to describe the detailed characteristics of AESD, including clinical course, electroencephalogram data, laboratory data, imaging findings, treatment, and outcomes. METHODS We reviewed the clinical database and medical charts of 43 consecutive pediatric patients (<18 years old) who developed AESD between October 1, 2002, and September 30, 2019. RESULTS We found that AESD occurred even though patients did not develop prolonged seizures. A comparison between the two groups (first seizure duration <30 min and first seizure duration ≥30 min) revealed three main findings: first, patients with AESD who had shorter seizures had better prognosis than those with prolonged seizures; second, patients with AESD who had shorter seizures tended to have earlier occurrence of a second seizure; and third, high signal intensity on diffusion-weighted magnetic resonance imaging was observed mainly in frontal areas, not diffusely, in patients with shorter seizures, and in a broader area in patients with prolonged seizures. CONCLUSIONS Our description of the detailed clinical picture of AESD may add new insight into its pathophysiology.
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Fukuzumi N, Osawa K, Sato I, Iwatani S, Ohnuma K, Imanishi T, Iijima K, Saegusa J, Morioka I. Detection of Bacterial Infection Based on Age-Specific Percentile-Based Reference Curve for Serum Procalcitonin Level in Preterm Infants. Clin Lab 2020; 66. [DOI: 10.7754/clin.lab.2019.190614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Masunaga Y, Inoue T, Yamoto K, Fujisawa Y, Sato Y, Kawashima-Sonoyama Y, Morisada N, Iijima K, Ohata Y, Namba N, Suzumura H, Kuribayashi R, Yamaguchi Y, Yoshihashi H, Fukami M, Saitsu H, Kagami M, Ogata T. IGF2 Mutations. J Clin Endocrinol Metab 2020; 105:5572642. [PMID: 31544945 DOI: 10.1210/clinem/dgz034] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 09/20/2019] [Indexed: 12/12/2022]
Abstract
OBJECTIVE IGF2 is a paternally expressed growth-promoting gene. Here, we report five cases with IGF2 mutations and review IGF2 mutation-positive patients described in the literature. We also compare clinical features between patients with IGF2 mutations and those with H19/IGF2:IG-DMR epimutations. RESULTS We recruited five cases with IGF2 mutations: case 1 with a splice site mutation (c.-6-1G>C) leading to skipping of exon 2 and cases 2-5 with different missense mutations (p.(Cys70Tyr), p.(Cys71Arg), p.(Cys33Ser), and p.(Cys45Ser)) affecting cysteine residues involved in the S-S bindings. All the mutations resided on the paternally inherited allele, and the mutation of case 5 was present in a mosaic condition. Clinical assessment revealed Silver-Russell syndrome (SRS) phenotype with Netchine-Harbison scores of ≥5/6 in all the apparently nonmosaic 14 patients with IGF2 mutations (cases 1-4 described in this study and 10 patients reported in the literature). Furthermore, compared with H19/IGF2:IG-DMR epimutations, IGF2 mutations were associated with low frequency of hemihypoplasia, high frequency of feeding difficulty and/or reduced body mass index, and mild degree of relative macrocephaly, together with occasional development of severe limb malformations, high frequency of cardiovascular anomalies and developmental delay, and low serum IGF-II values. CONCLUSIONS This study indicates that IGF2 mutations constitute a rare but important cause of SRS. Furthermore, while both IGF2 mutations and H19/IGF2:IG-DMR epimutations lead to SRS, a certain degree of phenotypic difference is observed between the two groups, probably due to the different IGF2 expression pattern in target tissues.
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Nishida K, Fujioka K, Sugioka Y, Abe S, Ashina M, Fukushima S, Ohyama S, Ikuta T, Tanimura K, Yamada H, Iijima K, Morioka I. Prediction of Neurodevelopmental Impairment in Congenital Cytomegalovirus Infection by Early Postnatal Magnetic Resonance Imaging. Neonatology 2020; 117:460-466. [PMID: 32492677 DOI: 10.1159/000508218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Accepted: 04/26/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Congenital cytomegalovirus infection (CCMVI) may result in neurodevelopmental impairments (NDIs) such as hearing loss, developmental delay, epilepsy, and cerebral palsy. We aimed to investigate the potential for brain magnetic resonance imaging (MRI) to predict NDI in patients with CCMVI. METHODS We studied infants with CCMVI who were referred to our hospital from April 2010 to October 2018 and underwent a brain MRI within 3 months since birth. We screened for 6 classic presentations of CCMVI including ventriculomegaly, periventricular cysts, hippocampal dysplasia, cerebellar hypoplasia, migration disorders, and white matter abnormalities. Images were interpreted by a blinded pediatric radiologist. NDI was defined as having a developmental quotient <80, hearing dysfunction, blindness, or epilepsy requiring anti-epileptic drugs at approximately 18 months of corrected age. RESULTS The study involved 42 infants with CCMVI (median gestational age 38 weeks, birthweight 2,516 g). At least one abnormal finding was detected in 28 (67%) infants. Abnormal findings consisted of 3 cerebellar hypoplasia (7%), 7 migration disorders (17%), 26 white matter abnormalities (62%), 12 periventricular cysts (28%), 1 hippocampal dysplasia (2%), and 20 ventriculomegaly (48%). Abnormal findings were significantly more prevalent in infants with clinical symptoms (21/24, 91%) than in those without (7/19, 37%, p < 0.01). For NDI prediction, having ≥2 of ventriculomegaly, periventricular cysts, and white matter abnormality produced the highest Youden index values (0.78). CONCLUSION Infants with CCMVI with at least 2 of the abovementioned specific brain image abnormalities may be at high risk of developing NDI.
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Sameshima T, Morisada N, Egawa T, Kugo M, Iijima K. MPPH syndrome with aortic coarctation and macrosomia due to CCND2 mutations. Pediatr Int 2020; 62:115-117. [PMID: 31957131 DOI: 10.1111/ped.14068] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/17/2019] [Accepted: 11/18/2019] [Indexed: 11/30/2022]
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Kamei K, Ishikura K, Sako M, Ito S, Nozu K, Iijima K. Rituximab therapy for refractory steroid-resistant nephrotic syndrome in children. Pediatr Nephrol 2020; 35:17-24. [PMID: 30564879 DOI: 10.1007/s00467-018-4166-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 12/24/2022]
Abstract
Patients with steroid-resistant nephrotic syndrome (SRNS) who develop resistance to immunosuppressive agents, defined as refractory SRNS, have poor renal outcomes. Although the chimeric anti-CD20 monoclonal antibody rituximab has shown efficacy for frequently relapsing nephrotic syndrome and steroid-dependent nephrotic syndrome, its efficacy for refractory SRNS remains uncertain due to limited data. According to previous case reports, 50.4% of patients with refractory SRNS showed clinical improvements after rituximab treatment. Remission rates in patients with initial steroid resistance and late steroid resistance were 43.9 and 57.7%, respectively, and 41.5 and 63.6% in patients with focal segmental glomerulosclerosis and minor glomerular abnormalities, respectively. However, various factors (race, disease severity, number of rituximab doses, concomitant treatments, and observation period) differed among these observational studies and their consensus may also have been affected by potential publication bias. Rituximab monotherapy may have some degree of efficacy and lead to satisfactory outcomes in a subset of patients with refractory SRNS. However, administration of concomitant treatments during rituximab-mediated B cell depletion, such as methylprednisolone pulse therapy, daily oral prednisolone therapy, and immunosuppressive agents, may lead to better outcomes in these patients. Large-scale, multi-center prospective studies are needed to evaluate the efficacy and safety of such regimens.
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