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Wu Y, Ding J. Severe Hypokalemia and Poor Appetite in a 20-Month-Old Male. Clin Pediatr (Phila) 2024:99228241248975. [PMID: 38680022 DOI: 10.1177/00099228241248975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Affiliation(s)
- Yuping Wu
- Children's Medical Ward I,Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
| | - Juanjuan Ding
- Children's Medical Ward I,Wuhan Children's Hospital (Wuhan Maternal and Child Healthcare Hospital), Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei, China
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Yamamura T, Horinouchi T, Aoto Y, Lennon R, Nozu K. The Contribution of COL4A5 Splicing Variants to the Pathogenesis of X-Linked Alport Syndrome. Front Med (Lausanne) 2022; 9:841391. [PMID: 35211492 PMCID: PMC8861460 DOI: 10.3389/fmed.2022.841391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 11/25/2022] Open
Abstract
X-linked Alport syndrome (XLAS) is caused by pathogenic variants in COL4A5 and is characterized by progressive kidney disease, hearing loss, and ocular abnormalities. Recent advances in genetic analysis and further understanding of genotype-phenotype correlations in affected male patients raises the importance of detecting splicing variants in COL4A5. Aberrant splicing of COL4A5 is caused not only by canonical splice site variants but also non-canonical splice site variants such as deep intronic changes or even substitutions in exons. Patients with splicing variants account for ~15% of all cases in XLAS. In addition, it has been shown that there is a significant difference in kidney survival depending on the aberrant splicing patterns of transcripts- in particular in-frame or out-of-frame nucleotide changes in transcripts. Therefore, cDNA analysis of patient mRNA is necessary to determine the impact of splice site variants and to confirm a diagnosis of XLAS and to predict the kidney prognosis. However, it is usually difficult to amplify COL4A5 transcripts extracted from peripheral blood leukocytes. For these cases, in vitro minigene assays or RNA sequence extracted from urine derived cells can confirm aberrant splicing patterns. Moreover, controlling aberrant splicing by nucleic acids or small molecular compounds in genetic diseases are attracting attention as a potential therapeutic strategy. Here, we review the frequency of splicing variants in COL4A5, the latest diagnostic strategies, and the prospects for new therapeutic approaches.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Wellcome Centre for Cell-Matrix Research, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology Medicine and Health, University of Manchester, Manchester, United Kingdom.,Department of Paediatric Nephrology, Royal Manchester Children's Hospital, Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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3
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Tsuji Y, Yamamura T, Nagano C, Horinouchi T, Sakakibara N, Ishiko S, Aoto Y, Rossanti R, Okada E, Tanaka E, Tsugawa K, Okamoto T, Sawai T, Araki Y, Shima Y, Nakanishi K, Nagase H, Matsuo M, Iijima K, Nozu K. Systematic Review of Genotype-Phenotype Correlations in Frasier Syndrome. Kidney Int Rep 2021; 6:2585-2593. [PMID: 34622098 PMCID: PMC8484119 DOI: 10.1016/j.ekir.2021.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/22/2022] Open
Abstract
Introduction Frasier syndrome (FS) is a rare inherited kidney disease caused by intron 9 splicing variants of WT1. For wild-type WT1, 2 active splice donor sites in intron 9 cause a mixture of 2 essential transcripts (with or without lysine-threonine-serine [+/KTS or −KTS]), and imbalance of the +KTS/−KTS ratio results in the development of FS. To date, 6 causative intron 9 variants have been identified; however, detailed transcript analysis has not yet been conducted and the genotype-phenotype correlation also remains to be elucidated. Methods We conducted an in vitro minigene splicing assay for 6 reported causative variants and in vivo RNA sequencing to determine the +KTS/−KTS ratio using patients’ samples. We also performed a systematic review of reported FS cases with a description of the renal phenotype. Results The in vitro assay revealed that although all mutant alleles produced −KTS transcripts only, the wild-type allele produced both +KTS and −KTS transcripts at a 1:1 ratio. In vivo RNA sequencing showed that patients’ samples with all heterozygous variants produced similar ratios of +KTS to −KTS (1:3.2−1:3.5) and wild-type kidney showed almost a 1:1 ratio (1:0.85). A systematic review of 126 cases clarified that the median age of developing ESKD was 16 years in all FS patients, and there were no statistically significant differences between the genotypes or sex chromosome karyotypes in terms of the renal survival period. Conclusion Our study suggested no differences in splicing pattern or renal survival period among reported intron 9 variants causative of FS.
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Affiliation(s)
- Yurika Tsuji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eri Okada
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Eriko Tanaka
- Department of Pediatrics, Kyorin University School of Medicine, Mitaka, Japan
| | - Koji Tsugawa
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Takayuki Okamoto
- Department of Pediatrics, Hokkaido University Graduate School of Meidicine, Sapporo, Japan
| | - Toshihiro Sawai
- Department of Pediatrics, Shiga University of Medical Science, Shiga, Japan
| | - Yoshinori Araki
- Department of Pediatrics, Hokkaido Medical Center, Sapporo, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Locomotion Biology Research Center, Kobe Gakuin University, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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4
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Takafuji S, Mori T, Nishimura N, Yamamoto N, Uemura S, Nozu K, Terui K, Toki T, Ito E, Muramatsu H, Takahashi Y, Matsuo M, Yamamura T, Iijima K. Usefulness of functional splicing analysis to confirm precise disease pathogenesis in Diamond-Blackfan anemia caused by intronic variants in RPS19. Pediatr Hematol Oncol 2021; 38:515-527. [PMID: 33622161 DOI: 10.1080/08880018.2021.1887984] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Diamond-Blackfan anemia (DBA) is mainly caused by pathogenic variants in ribosomal proteins and 22 responsible genes have been identified to date. The most common causative gene of DBA is RPS19 [NM_001022.4]. Nearly 180 RPS19 variants have been reported, including three deep intronic variants outside the splicing consensus sequence (c.72-92A > G, c.356 + 18G > C, and c.411 + 6G > C). We also identified one case with a c.412-3C > G intronic variant. Without conducting transcript analysis, the pathogenicity of these variants is unknown. However, it is difficult to assess transcripts because of their fragility. In such cases, in vitro functional splicing assays can be used to assess pathogenicity. Here, we report functional splicing analysis results of four RPS19 deep intronic variants identified in our case and in previously reported cases. One splicing consensus variant (c.411 + 1G > A) was also examined as a positive control. Aberrant splicing with a 2-bp insertion between exons 5 and 6 was identified in the patient samples and minigene assay results also identified exon 6 skipping in our case. The exon 6 skipping transcript was confirmed by further evaluation using quantitative RT-PCR. Additionally, minigene assay analysis of three reported deep intronic variants revealed that none of them showed aberrant splicing and that these variants were not considered to be pathogenic. In conclusion, the minigene assay is a useful method for functional splicing analysis of inherited disease.
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Affiliation(s)
- Satoru Takafuji
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Mori
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Noriyuki Nishimura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nobuyuki Yamamoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Suguru Uemura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kiminori Terui
- Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Tsutomu Toki
- Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Etsuro Ito
- Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshiyuki Takahashi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masafumi Matsuo
- Locomotion Biology Research Center, Kobe Gakuin University, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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Guo W, Song Q, Zhang R, Xin Q, Liu Z, Lang Y, Zhao X, Shao L. Genotypic and phenotypic analysis in 51 Chinese patients with primary distal renal tubular acidosis. Clin Genet 2021; 100:440-446. [PMID: 34159584 DOI: 10.1111/cge.14011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 12/25/2022]
Abstract
The aim of this study was to analyze the genetic variants of 51 Chinese patients with distal renal tubular acidosis (dRTA) and explore the correlation between their genotype and phenotype. Eight variants of SLC4A1, 19 variants of ATP6V0A4, and 16 variants of ATP6V1B1 have been identified, and of which 14 were novel ones. Eleven patients with autosomal dominant dRTA, and four patients with autosomal recessive dRTA were caused by genetic defects in SLC4A1; 18 and nine patients with recessive dRTA were resulted by defects in ATP6V0A4 and ATP6V1B1 respectively; no causal gene was identified in seven patients. Mutation frequency of SLC4A1 in Chinese populations was more common than Europeans. The incidence of deafness in ATP6V0A4 and ATP6V1B1 groups was 16.7% and 54.5%, respectively. The frequency of CKD in adults, children and infants was 100%, 51%, and 3%, separately. Our study will further expand the mutation spectrum of primary dRTA and provide valuable references to genetic counseling of Chinese populations.
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Affiliation(s)
- Wencong Guo
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Qijing Song
- Department of Emergency, Qingdao Jimo People's Hospital, Qingdao, China
| | - Ruixiao Zhang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Qing Xin
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zhiying Liu
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Yanhua Lang
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xiangzhong Zhao
- Central Laboratory, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Leping Shao
- Department of Nephrology, The Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
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Exon-Trapping Assay Improves Clinical Interpretation of COL11A1 and COL11A2 Intronic Variants in Stickler Syndrome Type 2 and Otospondylomegaepiphyseal Dysplasia. Genes (Basel) 2020; 11:genes11121513. [PMID: 33348901 PMCID: PMC7766184 DOI: 10.3390/genes11121513] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 11/17/2022] Open
Abstract
Stickler syndrome (SS) is a hereditary connective tissue disorder affecting bones, eyes, and hearing. Type 2 SS and the SS variant otospondylomegaepiphyseal dysplasia (OSMED) are caused by deleterious variants in COL11A1 and COL11A2, respectively. In both genes, available database information indicates a high rate of potentially deleterious intronic variants, but published evidence of their biological effect is usually insufficient for a definite clinical interpretation. We report four previously unpublished intronic variants in COL11A1 (c.2241 + 5G>T, c.2809 − 2A>G, c.3168 + 5G>C) and COL11A2 (c.4392 + 1G>A) identified in type 2 SS/OSMED individuals. The pathogenic effect of these variants was first predicted in silico and then investigated by an exon-trapping assay. We demonstrated that all variants can induce exon in-frame deletions, which lead to the synthesis of shorter collagen XI α1 or 2 chains. Lacking residues are located in the α-triple helical region, which has a crucial role in regulating collagen fibrillogenesis. In conclusion, this study suggests that these alternative COL11A1 and COL11A2 transcripts might result in aberrant triple helix collagen. Our approach may help to improve the diagnostic molecular pathway of COL11-related disorders.
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Fukushima S, Farea M, Maeta K, Rani AQM, Fujioka K, Nishio H, Matsuo M. Dual Fluorescence Splicing Reporter Minigene Identifies an Antisense Oligonucleotide to Skip Exon v8 of the CD44 Gene. Int J Mol Sci 2020; 21:ijms21239136. [PMID: 33266296 PMCID: PMC7729581 DOI: 10.3390/ijms21239136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/25/2020] [Accepted: 11/29/2020] [Indexed: 12/14/2022] Open
Abstract
Splicing reporter minigenes are used in cell-based in vitro splicing studies. Exon skippable antisense oligonucleotide (ASO) has been identified using minigene splicing assays, but these assays include a time- and cost-consuming step of reverse transcription PCR amplification. To make in vitro splicing assay easier, a ready-made minigene (FMv2) amenable to quantitative splicing analysis by fluorescence microscopy was constructed. FMv2 was designed to encode two fluorescence proteins namely, mCherry, a transfection marker and split eGFP, a marker of splicing reaction. The split eGFP was intervened by an artificial intron containing a multicloning site sequence. Expectedly, FMv2 transfected HeLa cells produced not only red mCherry but also green eGFP signals. Transfection of FMv2CD44v8, a modified clone of FMv2 carrying an insertion of CD44 exon v8 in the multicloning site, that was applied to screen exon v8 skippable ASO, produced only red signals. Among seven different ASOs tested against exon v8, ASO#14 produced the highest index of green signal positive cells. Hence, ASO#14 was the most efficient exon v8 skippable ASO. Notably, the well containing ASO#14 was clearly identified among the 96 wells containing randomly added ASOs, enabling high throughput screening. A ready-made FMv2 is expected to contribute to identify exon skippable ASOs.
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Affiliation(s)
- Sachiyo Fukushima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (S.F.); (K.F.)
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
| | - Manal Farea
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
| | - Kazuhiro Maeta
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
- KNC Department of Nucleic Acid Drug Discovery, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan
| | - Abdul Qawee Mahyoob Rani
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
- KNC Department of Nucleic Acid Drug Discovery, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan
| | - Kazumichi Fujioka
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (S.F.); (K.F.)
| | - Hisahide Nishio
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
- Department of Occupational Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan
| | - Masafumi Matsuo
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe 651-2180, Japan; (M.F.); (K.M.); (A.Q.M.R.); (H.N.)
- KNC Department of Nucleic Acid Drug Discovery, Faculty of Rehabilitation, Kobe Gakuin University, Kobe 651-2180, Japan
- Correspondence: ; Tel.: +81-78-974-6194
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8
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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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Affiliation(s)
- Tomohiko Inoue
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.,Division of Nephrology and Hypertension, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Kawasaki City, Kanagawa, 216-8511, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan.
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, 518 Arise, Ikawadani-cho, Nishi-ku, Kobe, Hyogo, 651-2180, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Yugo Shibagaki
- Division of Nephrology and Hypertension, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Kawasaki City, Kanagawa, 216-8511, Japan
| | - Daisuke Ichikawa
- Division of Nephrology and Hypertension, St. Marianna University Graduate School of Medicine, 2-16-1 Sugao, Kawasaki City, Kanagawa, 216-8511, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Shingo Ishimori
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo, 650-0017, Japan
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9
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Khan N, Akhtar N, Khan FF, Hussain S, Naeem M. Molecular Diagnosis and Identification of Genetic Variants Underlying Distal Renal Tubular Acidosis in Pakistani Patients Using Whole Exome Sequencing. Genet Test Mol Biomarkers 2020; 24:85-91. [PMID: 31999492 DOI: 10.1089/gtmb.2019.0195] [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] [Indexed: 12/25/2022] Open
Abstract
Introduction: Primary distal renal tubular acidosis (dRTA) is a rare genetic disorder characterized by an impaired urinary acidification process in distal nephrons that results in the production of alkaline urine. Loss of function variants in any of the three genes, ATP6V0A4, ATP6V1B1, or SLC4A1, which all play a role in normal acidification of urine by kidneys, may lead to dRTA. Objective: This study was designed to identify genetic variants underlying dRTA in Pakistani patients using whole exome sequencing, followed by confirmatory Sanger sequencing. Materials and Methods: Patients were identified following presentation with characteristic clinical features of dRTA including vomiting, dehydration, and highly alkaline urine with metabolic acidosis during the first few days of life. Whole exome sequencing and Sanger sequencing were employed for genetic analyses of the patients. In silico analyses of the identified variants were performed using web-based bioinfomatics programs. Results: Through whole exome sequencing, we identified two splice site variants (c.2257 + 1G>A and c.722 + 5G>A) in the ATP6V0A4 gene that likely underly the disease phenotype in the two families. Multiple in silico tools predicted these variants to affect the respective splice sites supporting their likely role in pathogenesis. Conclusion: The study extends the spectrum of ATP6V0A4 variants associated with dRTA and should benefit the genetic counseling and prenatal diagnosis of the affected families.
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Affiliation(s)
- Naima Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Naureen Akhtar
- Department of Pediatric Nephrology, The Children's Hospital and The Institute of Child Health, Lahore, Pakistan
| | - Fehmida Farid Khan
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
| | - Sofia Hussain
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan.,Department of Zoology, PMAS Arid Agriculture University, Rawalpindi, Pakistan
| | - Muhammad Naeem
- Medical Genetics Research Laboratory, Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan
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10
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Horinouchi T, Nozu K, Yamamura T, Minamikawa S, Nagano C, Sakakibara N, Nakanishi K, Shima Y, Morisada N, Ishiko S, Aoto Y, Nagase H, Takeda H, Rossanti R, Kaito H, Matsuo M, Iijima K. Determination of the pathogenicity of known COL4A5 intronic variants by in vitro splicing assay. Sci Rep 2019; 9:12696. [PMID: 31481700 PMCID: PMC6722096 DOI: 10.1038/s41598-019-48990-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/15/2019] [Indexed: 02/07/2023] Open
Abstract
X-linked Alport syndrome (XLAS) is a congenital renal disease caused by mutations in COL4A5. In XLAS cases suspected of being caused by aberrant splicing, transcript analysis needs to be conducted to determine splicing patterns and assess the pathogenicity. However, such analysis is not always available. We conducted a functional splicing assay using a hybrid minigene for seven COL4A5 intronic mutations: one was identified by us and six were found in the Human Gene Mutation Database. The minigene assay revealed exon skipping in four variants, exon skipping and a 10-bp insertion in one variant, and no change in one variant, which appeared not to be pathogenic. For one variant, our assay did not work. The results of all three cases for which transcript data were available were consistent with our assay results. Our findings may help to increase the accuracy of genetic test results and clarify the mechanisms causing aberrant splicing.
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Affiliation(s)
- Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan.
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, 207, Uehara, Nishihara-cho, Tyutou, Okinawa, 903-0125, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, 811-1, Kimiidera, Wakayama, Wakayama Prefecture, 641-8510, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroki Takeda
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, 518, Arise, Ikawadani-cho, Nishi, Kobe, Hyogo, 651-2180, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo, Kobe, Hyogo, 650-0017, Japan
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11
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Yamamura T, Nozu K, Ueda H, Fujimaru R, Hisatomi R, Yoshida Y, Kato H, Nangaku M, Miyata T, Sawai T, Minamikawa S, Kaito H, Matsuo M, Iijima K. Functional splicing analysis in an infantile case of atypical hemolytic uremic syndrome caused by digenic mutations in C3 and MCP genes. J Hum Genet 2018; 63:755-759. [PMID: 29556035 DOI: 10.1038/s10038-018-0436-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 02/19/2018] [Indexed: 01/05/2023]
Abstract
Pathogenic variants in specific complement-related genes lead to atypical hemolytic uremic syndrome (aHUS). Some reports have indicated that patients with digenic variants in these genes might present severer phenotypes. Upon detecting novel intronic variants, transcriptional analysis is necessary to prove pathogenicity; however, when intronic variants are located in intron 1 and, as a result, no transcript is produced, no appropriate method had been established to reveal the pathogenicity. Recently, the minigene assay was used to assess the pathogenicity of intronic variants. Here, we report an infantile case of aHUS caused by digenic mutations in two different complement-related genes, C3 and MCP. Targeted sequencing detected a known variant in C3 and a novel variant in the intron 1 splicing donor site of MCP. To assess the pathogenicity of this intronic variant, we conducted functional splicing assay using a minigene construct and quantitative PCR analysis of the MCP transcript, revealing the pathogenicity of the intronic variant. In conclusion, the minigene assay revealed the pathogenicity of the intron 1 splicing donor site variant for the first time. This case showed a severe phenotype of infantile-onset aHUS associated with digenic variants in two complement-related genes.
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Affiliation(s)
- Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Hiroaki Ueda
- Department of Pediatrics, Osaka City General Hospital, Osaka, Japan
| | - Rika Fujimaru
- Department of Pediatrics, Osaka City General Hospital, Osaka, Japan
| | - Ryutaro Hisatomi
- Department of Pediatrics, Osaka City General Hospital, Osaka, Japan
| | - Yoko Yoshida
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Hideki Kato
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
| | - Toshiyuki Miyata
- Departments of Molecular Pathogenesis and Cerebrovascular Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Toshihiro Sawai
- Department of Pediatrics, Shiga University of Medical Science, Otsu, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Department of Physical Therapy, Faculty of Rehabilitation, Kobe Gakuin University, Kobe, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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