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Ji X, Hou X, Guo X, Sun Y, Ma F, Hao J. Identification of a novel WAS mutation and the non-splicing effect of a second-site mutation in a Chinese pedigree with Wiskott-Aldrich syndrome. Orphanet J Rare Dis 2022; 17:447. [PMID: 36550574 PMCID: PMC9783790 DOI: 10.1186/s13023-022-02589-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Wiskott-Aldrich syndrome (WAS) is a rare X-linked immunodeficiency disorder caused by abnormal expression of the WAS protein (WASp) due to mutations in the WAS gene, and is generally characterized by microthrombocytopenia, eczema, recurrent infections, and high susceptibility to autoimmune complications and hematological malignancies. RESULTS Herein, we identified a novel WAS mutation (c.158 T > C) using next-generation sequencing in a Chinese pedigree with WAS. The expression of WASp in the patients and their families was detected by flow cytometry and western blot analysis. To explore the exon-splicing effect of intron mutations and the correlation between the genotype and clinical phenotype, four groups of wild-type (WT), exon mutant, intron mutant, and combined mutant recombinant plasmids were transfected into COS-7 cells in vitro. The proband showed dramatically decreased WASp expression, while the female carriers showed a slightly lower level of WASp. The expression of products in the mutant and WT recombinant plasmids was detected by real-time fluorescence quantitative polymerase chain reaction (PCR), which showed a significant reduction in the combined mutant group than in the WT, exon mutant, and intron mutant groups. The length of the expression products in the four groups showed no differences, each containing 360 base pairs. Sequence analysis confirmed that the c.158 T > C mutation appeared in the exon mutant and combined mutant groups, whereas the intron variant c.273 + 14C > T caused no other sequence changes. CONCLUSION This study confirmed that the intron mutation did not affect the splicing of exons and excluded the influence of the double mutations at the transcription level on the severe clinical manifestations in the cousin. This in vitro study provided new insights into the pathogenesis of intronic mutations in WAS.
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Affiliation(s)
- Xin Ji
- grid.452702.60000 0004 1804 3009Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, 215#, Heping West Road, Shijiazhuang, Hebei Province, 050000 China
| | - Xuening Hou
- grid.452702.60000 0004 1804 3009Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, 215#, Heping West Road, Shijiazhuang, Hebei Province, 050000 China
| | - Xin Guo
- grid.452702.60000 0004 1804 3009Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, 215#, Heping West Road, Shijiazhuang, Hebei Province, 050000 China
| | - Yifeng Sun
- grid.452702.60000 0004 1804 3009Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, 215#, Heping West Road, Shijiazhuang, Hebei Province, 050000 China
| | - Futian Ma
- grid.470210.0Department of Hematology and Oncology, Children’s Hospital of Hebei Province, 133#, Jianhua South Street, Shijiazhuang, Hebei Province, 050031 China
| | - Jihong Hao
- grid.452702.60000 0004 1804 3009Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, 215#, Heping West Road, Shijiazhuang, Hebei Province, 050000 China
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Shim YJ. Genetic classification and confirmation of inherited platelet disorders: current status in Korea. Clin Exp Pediatr 2020; 63:79-87. [PMID: 31477680 PMCID: PMC7073384 DOI: 10.3345/kjp.2019.00052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 08/21/2019] [Indexed: 12/26/2022] Open
Abstract
Inherited platelet disorders (IPDs), which manifest as primary hemostasis defects, often underlie abnormal bleeding and a family history of thrombocytopenia, bone marrow failure, hematologic malignancies, undefined mucocutaneous bleeding disorder, or congenital bony defects. Wide heterogeneity in IPD types with regard to the presence or absence of thrombocytopenia, platelet dysfunction, bone marrow failure, and dysmegakaryopoiesis is observed in patients. The individual processes involved in platelet production and hemostasis are genetically controlled; to date, mutations of more than 50 genes involved in various platelet biogenesis steps have been implicated in IPDs. Representative IPDs resulting from defects in specific pathways, such as thrombopoietin/MPL signaling; transcriptional regulation; granule formation, trafficking, and secretion; proplatelet formation; cytoskeleton regulation; and transmembrane glycoprotein signaling are reviewed, and the underlying gene mutations are discussed based on the National Center for Biotechnology Information database and Online Mendelian Inheritance in Man accession number. Further, the status and prevalence of genetically confirmed IPDs in Korea are explored based on searches of the PubMed and KoreaMed databases. IPDs are congenital bleeding disorders that can be dangerous due to unexpected bleeding and require genetic counseling for family members and descendants. Therefore, the pediatrician should be suspicious and aware of IPDs and perform the appropriate tests if the patient has unexpected bleeding. However, all IPDs are extremely rare; thus, the domestic incidences of IPDs are unclear and their diagnosis is difficult. Diagnostic confirmation or differential diagnoses of IPDs are challenging, time-consuming, and expensive, and patients are frequently misdiagnosed. Comprehensive molecular characterization and classification of these disorders should enable accurate and precise diagnosis and facilitate improved patient management.
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Affiliation(s)
- Ye Jee Shim
- Department of Pediatrics, Keimyung University School of Medicine, Keimyung University Dongsan Medical Center, Daegu, Korea
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Ohya T, Yanagimachi M, Iwasawa K, Umetsu S, Sogo T, Inui A, Fujisawa T, Ito S. Childhood-onset inflammatory bowel diseases associated with mutation of Wiskott-Aldrich syndrome protein gene. World J Gastroenterol 2017; 23:8544-8552. [PMID: 29358862 PMCID: PMC5752714 DOI: 10.3748/wjg.v23.i48.8544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/21/2017] [Accepted: 11/27/2017] [Indexed: 02/06/2023] Open
Abstract
AIM To screen primary immunodeficiency, Wiskott-Aldrich syndrome (WAS), and chronic granulomatous disease (CGD) among children with inflammatory bowel disease (IBD).
METHODS This was a single-center retrospective study. Eighteen children with IBD were investigated. We analyzed their expression of Wiskott-Aldrich syndrome protein (WASP) in lymphocytes and superoxide generation in phagocytes using flow cytometry. When the expression of WASP or superoxide generation was low or absent, we performed genetic analysis to determine the cause of this.
RESULTS Eighteen patients were classified as having ulcerative colitis (n = 10), Crohn’s disease (n = 5), or IBD-unclassified (n = 3). In total, three patients revealed low expression of WASP associated with a WAS gene c.1378 C>T p.Pro460Ser mutation, which has previously been reported as a pathogenic mutation in WAS and X-linked thrombocytopenia. However, with respect to the major symptoms of WAS, none of these three patients showed either thrombocytopenia or increased susceptibility to infection, but one patient showed generalized eczema. No CGD patients were discovered in this study.
CONCLUSION Despite the lack of typical clinical manifestations of WAS, low expression of WASP could be associated with the pathogenesis of a subtype of IBD patients.
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Affiliation(s)
- Takashi Ohya
- Department of Pediatrics, Yokohama City University, Yokohama, Kanagawa 236-004, Japan
| | - Masakatsu Yanagimachi
- Department of Pediatrics, Yokohama City University, Yokohama, Kanagawa 236-004, Japan
- Department of Pediatrics, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Kentaro Iwasawa
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hostopital, Turumi-ku, Yokohama, Kanagawa 230-0012, Japan
| | - Shuichiro Umetsu
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hostopital, Turumi-ku, Yokohama, Kanagawa 230-0012, Japan
| | - Tsuyoshi Sogo
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hostopital, Turumi-ku, Yokohama, Kanagawa 230-0012, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hostopital, Turumi-ku, Yokohama, Kanagawa 230-0012, Japan
| | - Tomoo Fujisawa
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hostopital, Turumi-ku, Yokohama, Kanagawa 230-0012, Japan
| | - Shuichi Ito
- Department of Pediatrics, Yokohama City University, Yokohama, Kanagawa 236-004, Japan
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Medina SS, Siqueira LH, Colella MP, Yamaguti-Hayakawa GG, Duarte BKL, Dos Santos Vilela MM, Ozelo MC. Intermittent low platelet counts hampering diagnosis of X-linked thrombocytopenia in children: report of two unrelated cases and a novel mutation in the gene coding for the Wiskott-Aldrich syndrome protein. BMC Pediatr 2017. [PMID: 28641574 PMCID: PMC5480256 DOI: 10.1186/s12887-017-0897-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Thrombocytopenia can occur in different circumstances during childhood and although immune thrombocytopenia is its most frequent cause, it is important to consider other conditions, especially when there is a persistent or recurrent low platelet count. We report two cases of intermittent thrombocytopenia, previously misdiagnosed as immune thrombocytopenia. Cases presentation Both cases described were boys who presented with an intermittent pattern of thrombocytopenia, with a persistently low mean platelet volume. In both patients, peripheral blood smear revealed small platelets and flow cytometry showed low expression of Wiskott-Aldrich syndrome protein (WASP) in leucocytes. Molecular analysis of the first case identified a mutation in exon 2 of the gene coding for WASP, leading to a p.Thr45Met amino acid change and confirming the diagnosis of X-linked thrombocytopenia. In the second case, a novel missense mutation in exon 2 of the gene coding for WASP was detected, which resulted in a p.Pro58Leu amino acid change. Conclusion These two rare presentations of thrombocytopenia highlight the importance of evaluating the peripheral blood smear in the presence of recurrent or persistent thrombocytopenia and show that failing to do so can lead to misdiagnoses. Since thrombocytopenia may be found in pediatric outpatient clinic, increased awareness among general pediatricians will help to improve the differential diagnosis of this condition.
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Affiliation(s)
- Samuel Souza Medina
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil.
| | - Lúcia Helena Siqueira
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil
| | - Marina Pereira Colella
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil
| | - Gabriela Goes Yamaguti-Hayakawa
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil
| | - Bruno Kosa Lino Duarte
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil
| | - Maria Marluce Dos Santos Vilela
- Centro de Investigação em Pediatria-CIPED, Faculty of Medical Sciences, University of Campinas (Unicamp), Rua Tessália Vieira de Camargo, 126, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-887, Brazil
| | - Margareth Castro Ozelo
- Instituto Nacional de Ciência e Tecnologia do Sangue, Hemocentro de Campinas, University of Campinas (Unicamp), Rua Carlos Chagas 480, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-878, Brazil.,Department of Internal Medicine, Faculty of Medical Sciences, University of Campinas (Unicamp), Rua Tessália Vieira de Camargo, 126, Cidade Universitária "Zeferino Vaz", Campinas, SP, 13.083-887, Brazil
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