Novel biallelic GNE variants identified in a patient with chronic thrombocytopenia without any symptoms of myopathy

Novel biallelic GNE variants identified in a patient with chronic thrombocytopenia without any symptoms of myopathy | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Novel biallelic GNE variants identified in a patient with chronic thrombocytopenia without any symptoms of myopathy Shota Tsuda, Atsushi Sakamoto, Hiroyuki Kawaguchi, Toru Uchiyama, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4708622/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 22 Nov, 2024 Read the published version in Annals of Hematology → Version 1 posted 8 You are reading this latest preprint version Abstract [Background] GNE encodes a rate-limiting enzyme that regulates the biosynthesis of a sialic acid precursor. As sialic acids are critical for the platelet membrane and muscle fibers, GNE variants cause GNE -related thrombocytopenia and GNE -related myopathy. Here, we report a neonate with thrombocytopenia that initially met the criteria for neonatal allo-immune thrombocytopenia (NAIT) but was resistant to treatments and then revealed novel biallelic heterozygous GNE variants without any symptoms of myopathy when diagnosed. [Case] NAIT was initially diagnosed due to alloantibodies against HPA5 and its mismatch between the patient and his mother. However, intravenous immunoglobulin therapy and platelet transfusions showed minimal improvement in the platelet count. Platelet counts remained around 60 × 10 9 /L, suggesting congenital thrombocytopenia. Gene panel sequencing at the age of 13 identified biallelic pathogenic variants of GNE . The patient did not exhibit any symptoms of muscular weakness suggesting GNE -related myopathy. [Discussion] We demonstrated a GNE -related thrombocytopenia patient with novel biallelic heterozygous GNE variants. Clinical trials have involved the use of sialic acids or their precursors, as well as gene therapy, to treat GNE -related myopathy, which may slow or halt the progression of the disease. Therefore, early diagnosis of this disease may significantly impact its clinical course. GNE thrombocytopenia myopathy NAIT Figures Figure 1 Introduction Congenital thrombocytopenia in neonates is less likely than the acquired ones [ 1 ]. Although it is fairly rare, 10% of treatment-resistant or chronic immune thrombocytopenia (ITP) cases are thought to be congenital [ 2 ]. The GNE gene encodes a rate-limiting enzyme that regulates the biosynthesis of a precursor of sialic acid called UDP-N-acetyl glucosamine 2-epimerase/N-acetylmannosamine kinase. The pathogenic variants in this gene reduce the production of sialic acid and cause oxidative stress in the plasma membrane. This oxidative stress causes protein misfolding and the activation of the ubiquitin-proteasome system. The modification of sialic acid of glycoproteins and glycolipids on the cell surface is also significant for its functions, such as cell adhesion and signal transduction [ 3 ]. Homozygous or biallelic heterozygous variants in GNE cause thrombocytopenia with or without myopathy (NIM#620757). This thrombocytopenia is an autosomal recessive disorder characterized by congenital thrombocytopenia apparent from infancy or early childhood [ 3 ]. Most affected individuals have bleeding episodes, including petechiae, easy bruising, epistaxis, hematomas, and increased bleeding after trauma or surgery. Although GNE -related thrombocytopenia often occurs during the neonatal or infantile periods, neonates with allo-immune anti-platelet antibodies have not been reported to our knowledge. Here, we report a neonatal case of thrombocytopenia that initially met the criteria for neonatal allo-immune thrombocytopenia (NAIT), but was resistant to treatments. We revealed novel GNE variants without any symptoms of myopathy appearing in the patient at the time of diagnosis. Case report A 13-year-old boy presented with persistent thrombocytopenia. The patient was born to a healthy mother at full term. The neonate had jaundice 3 days after birth, and blood tests were performed to determine the cause of incidentally noted thrombocytopenia. His parents were not consanguineous and without a history of thrombocytopenia or bleeding symptoms (Fig. 1 a). As we proceeded with our diagnosis for the newborn, we suspected NAIT based on alloantibodies against HPA5 and its mismatch between the patient and his mother. Thus, the newborn began treatment with intravenous immunoglobulins (IVIG) and platelet transfusion on day 6, which showed brief improvement, but the platelet count started to decrease later. Therefore, another IVIG and platelet transfusion were given on day 15, which showed a similar result as the first time. Once the platelet count stabilized around 50 × 10 9 /L, the patient was discharged (Fig. 1 b). He was carefully observed through outpatient visits as there were no episodes of severe bleeding. At 6 years of age, prednisolone 1.0 mg/kg/day for a week was given for tooth extraction with little improvement in platelet counts. We administered elthrombopag 6.25 mg/day for a week and 12.5 mg/day for four weeks, resulting in an increase in platelet count up to 100 × 10 9 /L. At 13 years of age, he had purpura, but no hearing loss, cataracts, or hepatosplenomegaly. Neurological examinations showed normal results without muscular weakness, upper/lower motor neuron symptoms, or abnormal reflexes/sensory signs/meningeal signs. We found normal coordinated movement, gait, and autonomic neuron functions. Complete blood count showed white blood cells 6.3 × 10 9 /L, hemoglobin 130 g/L, platelets 150 × 10 9 /L, mean platelet volume unmeasurable, and mean platelet diameter 4.3 µm (control: 2.7 µm) (Table 1 , Figs. 1 c and 1 d). The serum chemistry tests, including liver and renal functions and urine analyses, were all normal. Coagulation studies revealed a Duke bleeding time of 5 min and von Willebrand factor antigen 84%. Bone marrow examination showed normal nucleated cells and megakaryocytes with normal maturity (Figs. 1 h and 1 i). Flow cytometry showed increased expression of GPIIb and GPIIIa on the platelets (Table 1 ). Chromosome analysis was also normal. After informed consent was obtained, the genomic DNA of the patient was tested by gene panel sequencing, as previously shown [ 4 ]. The gene panel testing revealed novel biallelic variants in GNE , namely, [NM_01128227.3:c.1277del,p.(Asn426IlefsTer13)] and [NM_01128227.3:c.1163 + 5G > T], which were confirmed by Sanger sequencing (Fig. 1 j). These variants were classified as pathogenic and likely pathogenic according to the ACMG-AMP guidelines, respectively (Supplementary table). Table 1 Clinical and laboratory characteristics of the members of the reported family Patient Mother Father Age, years 1 55 45 Bleeding tendency Purpura No symptoms No symptoms White blood cells, 10 9 /L 6.3 4.9 6.1 Hemoglobin, g/L 130 137 131 Platelet count, 10 9 /L 15 187 148 MPV, fL Unmeasurable 10.6 11.6 MPD, µm 4.3 2.7 2.8 Bleeding time, min 5.0 2.0 2.5 GPIb, % 103.6 103.6 96.4 GPIX, % 129.6 111.1 106.2 GPIIb, % 177.4 124.1 100 GPIIIa, % 218.6 126.5 116.7 GPIIb/IIIa, % 202.7 126.7 120.5 Bleeding time was measured by Duke’s method. Abbreviations: MPV, mean platelet volume; MPD, mean platelet diameter; GP, glycoprotein. A family study showed that platelet counts were 187 × 10 9 /L in the father and 148 × 10 9 /L in the mother. Platelet sizes and morphologies were consistent with the controls (Figs. 1 e and 1 f). The father had a heterozygous variant in GNE , [NM_01128227.3:c.1277del,p.(Asn426IlefsTer13)] (Figs. 1 j and 1 k). The mother had a heterozygous variant in GNE , [NM_01128227.3:c.1163 + 5G > T] (Figs. 1 j and 1 l). Discussion In this case, a thrombocytopenic neonate met the criteria for the NAIT diagnosis; however, treatment showed little improvement. Hence, congenital thrombocytopenia was subsequently suspected, which led to the diagnosis of GNE -related thrombocytopenia. This case is unique in a sense that there has not been a report of any case of GNE -related thrombocytopenia meeting the criteria for the diagnosis of NAIT. Immune-mediated thrombocytopenia, such as NAIT, is one of the most common causes of early-onset neonatal thrombocytopenia. The estimated incidence of the thrombocytopenia is 0.3%, half of which is due to NAIT [ 5 , 6 ]. NAIT was suspected in this case because of the HPA5 mismatch between the patient and his mother. Response to IVIG treatment was poor and platelet transfusion showed only transient improvement in the platelet count. In combination with platelet transfusion, IVIG is thought to be an effective treatment for NAIT. In this case, despite the unstable platelet count, it remained around 60 × 10 9 /L, which led to suspicion of congenital thrombocytopenia. GNE -related thrombocytopenia is very rare in congenital thrombocytopenia. Sialic acids mediate the prevention of rapid platelet clearance by Ashwell-Morell receptors on the hepatocytes [ 7 ]. A variant in the gene causes increased platelet clearance. Platelets are large (macrothrombocytopenia) and circulating immature platelets are increased, suggesting increased production. Patient platelets show hyposialylation due to GNE variants, which causes accelerated removal of platelets from the circulation, shortened platelet lifespan, and resultant thrombocytopenia. Our patient had novel biallelic heterozygous variants in GNE. The mother had mild thrombocytopenia, suggesting that the variant may affect splicing of GNE , which is likely to be pathogenic. In our patient, GNE -related thrombocytopenia was determined in the low teens. Biallelic variants in GNE also cause GNE -related myopathy. It is an autosomal recessive progressive adult-onset myopathy with a predilection for distal muscle involvement, usually affecting the lower limbs and resulting in gait abnormalities or loss of ambulation. In recent studies, GNE variants have been reported to cause myopathy and thrombocytopenia [ 8 ]. There are two large registries of GNE myopathy, one in Japan and one in Israel, 2.5% and 0% of the patients had associated thrombocytopenia, respectively [ 9 ]. In contrast to thrombocytopenia, which is present since birth or early childhood, features of myopathy usually do not develop until the mid-twenties. Its average onset age is thought to be 27.7 ± 9.6 years [ 9 ]. GNE variants were diagnosed in our patient without clinical symptoms of neurological/muscular impairment. Clinical trials have involved the use of sialic acids or their precursors, as well as gene therapy trials, to treat GNE -related myopathy [ 10 ]. These trials are still in the early stages, but some products are thought to have a slight impact on muscle functional measurements without serious adverse effects [ 11 ]. Although it still is not clear which metabolic supplementation can affect its clinical course, slowing or halting the progression of the disease is the realistic outcome and this could have an incredible effect if the disease is diagnosed at an early stage [ 10 ]. The search for better GNE metabolites or sialic acid compounds [ 12 ], drugs to block or modify degenerative processes, and gene or cell-based therapy is ongoing. In the future, these therapies can be combined to provide better outcomes for the disease. To achieve appropriate treatments, we should carefully monitor the patient’s symptoms. Despite the initial diagnosis of NAIT, biallelic GNE variants were diagnosed for chronic resistant thrombocytopenia in the patient. We conducted the patient’s gene analysis, although the patient had no muscular/neurological symptoms. We believe that gene analysis can be a key component in diagnosing neonatal thrombocytopenia when prolonged thrombocytopenia is found. Early diagnosis of this disease may significantly impact its clinical course by the potential treatments in the clinical trials. Declarations Compliance with ethical standards This study was approved by the Ethics Committees of the NCCHD in May, 2018 (#1818). Informed consent for this report was obtained from the patient and her parents. Permission to reproduce material from other sources In accordance with the regulations of the place where the article was accepted. Data availability statement De-identified patient data is available upon request to corresponding author. Competing interests The authors declare that they have no competing interests. Funding sources This study was supported by The Grants of Japan Agency for Medical Research and Development (18ek0109366h0001, 19ek0109366h0002, and 20ek0109366h003), and The Grant of NCCHD (2021B-3, 2024B-3) to Ishiguro A. Author contributions ST, AS, SK, and AI (Ishiguro) contributed to the conception of this study; ST, AS and AI (Ishiguro) created the database and drafted the manuscript; TU, TK, KY, and SK performed gene analyses. HK and others managed patients and collected critical samples. All authors reviewed and approved the final manuscript Acknowledgments We express our gratitude to the participating patient and her parents. We are grateful to the senior medical editor at the Center for Postgraduate Education and Training at the National Center for Child Health and Development for English language review. References Donato H.(2021) Neonatal thrombocytopenia: A review. I. Definitions, differential diagnosis, causes, immune thrombocytopenia. Arch Argent Pediatr.119(3):e202-e214. https://doi.org/10.5546/aap.2021.eng.e202. Arnold DM, Nazy I, Clare R, Jaffer AM, Aubie B, Li N, Kelton JG (2017) Misdiagnosis of primary immune thrombocytopenia and frequency of bleeding: lessons from the McMaster ITP Registry. Blood Adv.1:2414-2420. https://doi.org/10.1182/bloodadvances.2017010942. Hinderlich S, Weidemann W, Yardeni T, Horstkorte R, Huizing M (2015) UDP-GlcNAc 2-Epimerase/ManNAc Kinase (GNE): A master regulator of sialic acid synthesis. Top Curr Chem. 366:97-137. https://doi.org/10.1007/128_2013_464 Kanamaru Y, Uchiyama T, Kaname T, Yanagi K, Ohara O, Kunishima S, Ishiguro A (2021) ETV6-related thrombocytopenia associated with a transient decrease in von Willebrand factor. Int J Hematol. 114(2):297-300. https://doi.org/10.1007/s12185-021-03136-4 Sola-Visner M, Saxonhouse MA, Brown RE (2008) Neonatal thrombocytopenia: what we do and don't know. Early Hum Dev. 84(8):499-506.https:// doi.org/10.1016/j.earlhumdev.2008.06.004 Dreyfus M, Kaplan C, Verdy E, Schlegel N, Durand-Zaleski I, Tchernia G (1997) Frequency of immune thrombocytopenia in newborns: a prospective study. Immune Thrombocytopenia Working Group. Blood. 89(12):4402-4406. https://doi.org/10.1182/blood.V89.12.4402 Zieger B, Boeckelmann D, Anani W, Falet H, Zhu J, Glonnegger H, Full H, Andresen F, Erlacher M, Lausch E, Fels S, Strahm B, Lang P, Hoffmeister K (2022) Novel GNE gene variants associated with severe congenital thrombocytopenia and platelet sialylation defect. Thromb Haemost. 122(7):1139-1146. https://doi.org/10.1055/s-0041-1742207 Eisenberg I, Avidan N, Potikha T, Hochner H, Chen M, Olender T, Barash M, Shemesh M, Sadeh M, Grabov-Nardini G, Shmilevich I, Friedmann A, Karpati G, Bradley G, Baumbach L, Lancet D, Asher WB, Beckmann JS, Argov Z, Mitrani-Rosenbaum S. (2001) The UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase gene is mutated in recessive hereditary inclusion body myopathy. Nat Genet. 29(1):83-7. https://doi:.org/10.1038/ng718. Mori-Yoshimura M, Hayashi YK, Yonemoto N, Nakamura H, Murata M, Takeda S, Nishino I, Kimura E (2014) Nationwide patient registry for GNE myopathy in Japan. Orphanet J Rare Dis. 9:150.https:// doi.org/10.1186/s13023-014-0150-4. Nishino I, Carrillo-Carrasco N, Argov Z. (2015) GNE myopathy: current update and future therapy. J Neurol Neurosurg Psychiatry. 86(4):385-92. https://doi.org/10.1136/jnnp-2013-307051. Argov Z, Bronstein F, Esposito A, Feinsod-Meiri Y, Florence JM, Fowler E, Greenberg MB, Malkus EC, Rebibo O, Siener CS, Caraco Y, Kolodny EH, Lau HA, Pestronk A, Shieh P, Skrinar AM, Mayhew JE (2017) Characterization of strength and function in ambulatory adults with GNE myopathy. J Clin Neuromuscul Dis. 19(1):19-26. https://doi.org/10.1097/CND.0000000000000181. Nemunaitis G, Jay CM, Maples PB, Gahl WA, Huizing M, Yardeni T, Tong AW, Phadke AP, Pappen BO, Bedell C, Allen H, Hernandez C, Templeton NS, Kuhn J, Senzer N, Nemunaitis J (2011) Hereditary inclusion body myopathy: single patient response to intravenous dosing of GNE gene lipoplex. Hum Gene Ther. 22(11):1331-1341. https://doi.org/10.1089/hum.2010.192 Additional Declarations No competing interests reported. Supplementary Files SupplementarytableGNE07062024.docx Cite Share Download PDF Status: Published Journal Publication published 22 Nov, 2024 Read the published version in Annals of Hematology → Version 1 posted Editorial decision: Revision requested 29 Aug, 2024 Reviewers agreed at journal 31 Jul, 2024 Reviews received at journal 24 Jul, 2024 Reviewers agreed at journal 23 Jul, 2024 Reviewers invited by journal 22 Jul, 2024 Editor assigned by journal 11 Jul, 2024 Submission checks completed at journal 11 Jul, 2024 First submitted to journal 08 Jul, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4708622","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":335496523,"identity":"1976ea6d-8e26-49ab-aca0-3ea844ed3077","order_by":0,"name":"Shota Tsuda","email":"","orcid":"","institution":"National Center for Child Health and Development (NCCHD)","correspondingAuthor":false,"prefix":"","firstName":"Shota","middleName":"","lastName":"Tsuda","suffix":""},{"id":335496524,"identity":"db0df04d-1c62-4662-a611-fbff7529a1d2","order_by":1,"name":"Atsushi Sakamoto","email":"","orcid":"","institution":"NCCHD","correspondingAuthor":false,"prefix":"","firstName":"Atsushi","middleName":"","lastName":"Sakamoto","suffix":""},{"id":335496525,"identity":"2007eb9d-cbba-4e69-a1c7-e7c01c2466ff","order_by":2,"name":"Hiroyuki Kawaguchi","email":"","orcid":"","institution":"National Defense Medical College","correspondingAuthor":false,"prefix":"","firstName":"Hiroyuki","middleName":"","lastName":"Kawaguchi","suffix":""},{"id":335496526,"identity":"c58a207a-5852-405e-b399-ec34caa8ee27","order_by":3,"name":"Toru Uchiyama","email":"","orcid":"","institution":"NCCHD","correspondingAuthor":false,"prefix":"","firstName":"Toru","middleName":"","lastName":"Uchiyama","suffix":""},{"id":335496527,"identity":"14130ad9-8e5a-4cbd-87e4-fc0f64e5cb6e","order_by":4,"name":"Tadashi Kaname","email":"","orcid":"","institution":"NCCHD","correspondingAuthor":false,"prefix":"","firstName":"Tadashi","middleName":"","lastName":"Kaname","suffix":""},{"id":335496528,"identity":"4f2a3e9c-3670-48cb-b529-3d6edeecd100","order_by":5,"name":"Kumiko Yanagi","email":"","orcid":"","institution":"NCCHD","correspondingAuthor":false,"prefix":"","firstName":"Kumiko","middleName":"","lastName":"Yanagi","suffix":""},{"id":335496529,"identity":"e82512d1-a7f2-4cfd-800d-e27a4687f3cb","order_by":6,"name":"Shinji Kunishima","email":"","orcid":"","institution":"Gifu University of Medical Science","correspondingAuthor":false,"prefix":"","firstName":"Shinji","middleName":"","lastName":"Kunishima","suffix":""},{"id":335496530,"identity":"b3bb1f86-4993-4c7e-9a88-7780d7731bd1","order_by":7,"name":"Akira Ishiguro","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA7klEQVRIie3QsWoCMRjA8e8Q4nKY9Qty9hVSAkLfJtL1dBE6OWTKdOBD+A7VzRwBp9QnkCIImVxuUG60x1Fal3hjofkv+b7hB0kAYrE/GIEUTDv2mtMkqpmxGyGyG4Ev8j3wHxJqQD/K8qI/R9B312O9OGSKrgy8bAIXw5m0mZ4LSKfr52LnhUIvgbkQSbllWk62Zvo+TJSdKHQcmA4Q6lqi6Nl3JJDzsmoI5qQltHhAMOcW9lIA+jErdlZoJNKE3vK0dKKq3+QI6KvHemGzJbXliQV+rKmX/t4ISrBMhUlS363UQFI9ILFYLPavugGBd1K4yXksiAAAAABJRU5ErkJggg==","orcid":"","institution":"National Center for Child Health and Development (NCCHD)","correspondingAuthor":true,"prefix":"","firstName":"Akira","middleName":"","lastName":"Ishiguro","suffix":""}],"badges":[],"createdAt":"2024-07-09 02:40:33","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4708622/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4708622/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s00277-024-06104-0","type":"published","date":"2024-11-22T15:56:59+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":62189206,"identity":"9e03d643-285d-4e4e-8bbd-ea17fcae09f3","added_by":"auto","created_at":"2024-08-10 12:20:40","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":650318,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Family pedigrees. \u003cem\u003eGNE\u003c/em\u003e variants that the patient has inherited are shown. (b) Changes in platelet counts according to platelet transfusion and intravenous immunoglobulin. The peripheral blood smear (c, d) and the bone marrow smear (h, i) of the patient, his mother (e), father (f), and control (g) are shown. (c, d) The patient presented with large platelets. (j) Sanger sequencing electropherograms indicating novel biallelic heterozygous variants in \u003cem\u003eGNE\u003c/em\u003e, namely, [NM_01128227.3:c.1277del,p.(Asn426IlefsTer13)] and [NM_01128227.3:c.1163+5G\u0026gt;T]. Linear domain organization of \u003cem\u003eGNE\u003c/em\u003eencoding the enzyme UDP-N-acetylglucosamine 2-epimerase family domain and ROK (NagC/XylR) family domain. The approximate position of frameshift variant \u003cstrong\u003ep.(\u003c/strong\u003eAsn426IlefsTer13\u003cstrong\u003e)\u003c/strong\u003e is found in the patient (k). Schematic diagram of \u003cem\u003eGNE\u003c/em\u003e exons. Previously reported variants associated with splicing are listed. The approximated position of the variant in this patient (c.1163+5G\u0026gt;T) is in red (l).\u003c/p\u003e","description":"","filename":"TsudaGNEFigure120240603.png","url":"https://assets-eu.researchsquare.com/files/rs-4708622/v1/60e132cc205184fae2b47957.png"},{"id":69834532,"identity":"c2327abf-ba11-4303-94ad-8c3c791e7c0b","added_by":"auto","created_at":"2024-11-25 16:06:32","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1150184,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4708622/v1/cc3cfd78-4045-408b-b1a9-9d0e4ead33d9.pdf"},{"id":62189207,"identity":"0243a212-d1da-4601-8e7b-e83c5537a36d","added_by":"auto","created_at":"2024-08-10 12:20:40","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":18236,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementarytableGNE07062024.docx","url":"https://assets-eu.researchsquare.com/files/rs-4708622/v1/209687be2cfd4f046fd9304b.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Novel biallelic GNE variants identified in a patient with chronic thrombocytopenia without any symptoms of myopathy","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCongenital thrombocytopenia in neonates is less likely than the acquired ones [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Although it is fairly rare, 10% of treatment-resistant or chronic immune thrombocytopenia (ITP) cases are thought to be congenital [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe \u003cem\u003eGNE\u003c/em\u003e gene encodes a rate-limiting enzyme that regulates the biosynthesis of a precursor of sialic acid called UDP-N-acetyl glucosamine 2-epimerase/N-acetylmannosamine kinase. The pathogenic variants in this gene reduce the production of sialic acid and cause oxidative stress in the plasma membrane. This oxidative stress causes protein misfolding and the activation of the ubiquitin-proteasome system. The modification of sialic acid of glycoproteins and glycolipids on the cell surface is also significant for its functions, such as cell adhesion and signal transduction [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eHomozygous or biallelic heterozygous variants in \u003cem\u003eGNE\u003c/em\u003e cause thrombocytopenia with or without myopathy (NIM#620757). This thrombocytopenia is an autosomal recessive disorder characterized by congenital thrombocytopenia apparent from infancy or early childhood [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Most affected individuals have bleeding episodes, including petechiae, easy bruising, epistaxis, hematomas, and increased bleeding after trauma or surgery.\u003c/p\u003e \u003cp\u003eAlthough \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia often occurs during the neonatal or infantile periods, neonates with allo-immune anti-platelet antibodies have not been reported to our knowledge. Here, we report a neonatal case of thrombocytopenia that initially met the criteria for neonatal allo-immune thrombocytopenia (NAIT), but was resistant to treatments. We revealed novel \u003cem\u003eGNE\u003c/em\u003e variants without any symptoms of myopathy appearing in the patient at the time of diagnosis.\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eA 13-year-old boy presented with persistent thrombocytopenia. The patient was born to a healthy mother at full term. The neonate had jaundice 3 days after birth, and blood tests were performed to determine the cause of incidentally noted thrombocytopenia. His parents were not consanguineous and without a history of thrombocytopenia or bleeding symptoms (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ea). As we proceeded with our diagnosis for the newborn, we suspected NAIT based on alloantibodies against HPA5 and its mismatch between the patient and his mother. Thus, the newborn began treatment with intravenous immunoglobulins (IVIG) and platelet transfusion on day 6, which showed brief improvement, but the platelet count started to decrease later. Therefore, another IVIG and platelet transfusion were given on day 15, which showed a similar result as the first time. Once the platelet count stabilized around 50 × 10\u003csup\u003e9\u003c/sup\u003e/L, the patient was discharged (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eb). He was carefully observed through outpatient visits as there were no episodes of severe bleeding. At 6 years of age, prednisolone 1.0 mg/kg/day for a week was given for tooth extraction with little improvement in platelet counts. We administered elthrombopag 6.25 mg/day for a week and 12.5 mg/day for four weeks, resulting in an increase in platelet count up to 100 × 10\u003csup\u003e9\u003c/sup\u003e/L.\u003c/p\u003e\u003cp\u003eAt 13 years of age, he had purpura, but no hearing loss, cataracts, or hepatosplenomegaly. Neurological examinations showed normal results without muscular weakness, upper/lower motor neuron symptoms, or abnormal reflexes/sensory signs/meningeal signs. We found normal coordinated movement, gait, and autonomic neuron functions. Complete blood count showed white blood cells 6.3 × 10\u003csup\u003e9\u003c/sup\u003e/L, hemoglobin 130 g/L, platelets 150 × 10\u003csup\u003e9\u003c/sup\u003e/L, mean platelet volume unmeasurable, and mean platelet diameter 4.3 µm (control: 2.7 µm) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ec and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ed). The serum chemistry tests, including liver and renal functions and urine analyses, were all normal. Coagulation studies revealed a Duke bleeding time of 5 min and von Willebrand factor antigen 84%. Bone marrow examination showed normal nucleated cells and megakaryocytes with normal maturity (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003eh and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ei). Flow cytometry showed increased expression of GPIIb and GPIIIa on the platelets (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Chromosome analysis was also normal. After informed consent was obtained, the genomic DNA of the patient was tested by gene panel sequencing, as previously shown [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. The gene panel testing revealed novel biallelic variants in \u003cem\u003eGNE\u003c/em\u003e, namely, [NM_01128227.3:c.1277del,p.(Asn426IlefsTer13)] and [NM_01128227.3:c.1163 + 5G \u0026gt; T], which were confirmed by Sanger sequencing (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ej). These variants were classified as pathogenic and likely pathogenic according to the ACMG-AMP guidelines, respectively (Supplementary table).\u003c/p\u003e\u003cdiv class=\"gridtable\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eClinical and laboratory characteristics of the members of the reported family\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003c/colgroup\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePatient\u003c/p\u003e \u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eMother\u003c/p\u003e \u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eFather\u003c/p\u003e \u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, years\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e55\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e45\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBleeding tendency\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePurpura\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo symptoms\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNo symptoms\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWhite blood cells, 10\u003csup\u003e9\u003c/sup\u003e/L\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.3\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.9\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.1\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin, g/L\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e130\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e137\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e131\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlatelet count, 10\u003csup\u003e9\u003c/sup\u003e/L\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e187\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e148\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMPV, fL\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eUnmeasurable\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.6\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.6\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMPD, µm\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.7\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.8\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBleeding time, min\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5.0\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.5\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGPIb, %\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e103.6\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e103.6\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e96.4\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGPIX, %\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e129.6\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e111.1\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e106.2\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGPIIb, %\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e177.4\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e124.1\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e100\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGPIIIa, %\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e218.6\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e126.5\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e116.7\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGPIIb/IIIa, %\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e202.7\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e126.7\u003c/p\u003e \u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e120.5\u003c/p\u003e \u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eBleeding time was measured by Duke’s method. Abbreviations: MPV, mean platelet volume; MPD, mean platelet diameter; GP, glycoprotein.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003cp\u003eA family study showed that platelet counts were 187 × 10\u003csup\u003e9\u003c/sup\u003e/L in the father and 148 × 10\u003csup\u003e9\u003c/sup\u003e/L in the mother. Platelet sizes and morphologies were consistent with the controls (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ee and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ef). The father had a heterozygous variant in \u003cem\u003eGNE\u003c/em\u003e, [NM_01128227.3:c.1277del,p.(Asn426IlefsTer13)] (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ej and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ek). The mother had a heterozygous variant in \u003cem\u003eGNE\u003c/em\u003e, [NM_01128227.3:c.1163 + 5G \u0026gt; T] (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003ej and \u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003el).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this case, a thrombocytopenic neonate met the criteria for the NAIT diagnosis; however, treatment showed little improvement. Hence, congenital thrombocytopenia was subsequently suspected, which led to the diagnosis of \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia.\u003c/p\u003e \u003cp\u003eThis case is unique in a sense that there has not been a report of any case of \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia meeting the criteria for the diagnosis of NAIT. Immune-mediated thrombocytopenia, such as NAIT, is one of the most common causes of early-onset neonatal thrombocytopenia. The estimated incidence of the thrombocytopenia is 0.3%, half of which is due to NAIT [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. NAIT was suspected in this case because of the HPA5 mismatch between the patient and his mother. Response to IVIG treatment was poor and platelet transfusion showed only transient improvement in the platelet count. In combination with platelet transfusion, IVIG is thought to be an effective treatment for NAIT. In this case, despite the unstable platelet count, it remained around 60 \u0026times; 10\u003csup\u003e9\u003c/sup\u003e/L, which led to suspicion of congenital thrombocytopenia.\u003c/p\u003e \u003cp\u003e \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia is very rare in congenital thrombocytopenia. Sialic acids mediate the prevention of rapid platelet clearance by Ashwell-Morell receptors on the hepatocytes [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. A variant in the gene causes increased platelet clearance. Platelets are large (macrothrombocytopenia) and circulating immature platelets are increased, suggesting increased production. Patient platelets show hyposialylation due to \u003cem\u003eGNE\u003c/em\u003e variants, which causes accelerated removal of platelets from the circulation, shortened platelet lifespan, and resultant thrombocytopenia. Our patient had novel biallelic heterozygous variants in \u003cem\u003eGNE.\u003c/em\u003e The mother had mild thrombocytopenia, suggesting that the variant may affect splicing of \u003cem\u003eGNE\u003c/em\u003e, which is likely to be pathogenic.\u003c/p\u003e \u003cp\u003eIn our patient, \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia was determined in the low teens. Biallelic variants in \u003cem\u003eGNE\u003c/em\u003e also cause \u003cem\u003eGNE\u003c/em\u003e-related myopathy. It is an autosomal recessive progressive adult-onset myopathy with a predilection for distal muscle involvement, usually affecting the lower limbs and resulting in gait abnormalities or loss of ambulation. In recent studies, \u003cem\u003eGNE\u003c/em\u003e variants have been reported to cause myopathy and thrombocytopenia [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. There are two large registries of GNE myopathy, one in Japan and one in Israel, 2.5% and 0% of the patients had associated thrombocytopenia, respectively [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. In contrast to thrombocytopenia, which is present since birth or early childhood, features of myopathy usually do not develop until the mid-twenties. Its average onset age is thought to be 27.7\u0026thinsp;\u0026plusmn;\u0026thinsp;9.6 years [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. \u003cem\u003eGNE\u003c/em\u003e variants were diagnosed in our patient without clinical symptoms of neurological/muscular impairment. Clinical trials have involved the use of sialic acids or their precursors, as well as gene therapy trials, to treat \u003cem\u003eGNE\u003c/em\u003e-related myopathy [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. These trials are still in the early stages, but some products are thought to have a slight impact on muscle functional measurements without serious adverse effects [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Although it still is not clear which metabolic supplementation can affect its clinical course, slowing or halting the progression of the disease is the realistic outcome and this could have an incredible effect if the disease is diagnosed at an early stage [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. The search for better GNE metabolites or sialic acid compounds [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], drugs to block or modify degenerative processes, and gene or cell-based therapy is ongoing. In the future, these therapies can be combined to provide better outcomes for the disease. To achieve appropriate treatments, we should carefully monitor the patient\u0026rsquo;s symptoms.\u003c/p\u003e \u003cp\u003eDespite the initial diagnosis of NAIT, biallelic \u003cem\u003eGNE\u003c/em\u003e variants were diagnosed for chronic resistant thrombocytopenia in the patient. We conducted the patient\u0026rsquo;s gene analysis, although the patient had no muscular/neurological symptoms. We believe that gene analysis can be a key component in diagnosing neonatal thrombocytopenia when prolonged thrombocytopenia is found. Early diagnosis of this disease may significantly impact its clinical course by the potential treatments in the clinical trials.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCompliance with ethical standards\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by the Ethics Committees of the\u0026nbsp;NCCHD\u0026nbsp;in May, 2018 (#1818). Informed consent for this report was obtained from the patient and her parents.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePermission to reproduce material from other sources\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn accordance with the regulations of the place where the article was accepted.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDe-identified patient data is available upon request to corresponding author.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding sources\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis study was supported by The Grants of Japan Agency for Medical Research and Development (18ek0109366h0001, 19ek0109366h0002, and 20ek0109366h003), and The Grant of NCCHD (2021B-3, 2024B-3) to Ishiguro A.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eST, AS, SK, and AI (Ishiguro) contributed to the conception of this study; ST, AS and AI (Ishiguro) created the database and drafted the manuscript; TU, TK, KY, and SK performed gene analyses. HK and others managed patients and collected critical samples. All authors reviewed and approved the final manuscript\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe express our gratitude to the participating patient and her parents. We are grateful to the senior medical editor at the Center for Postgraduate Education and Training at the National Center for Child Health and Development for English language review.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eDonato H.(2021) Neonatal thrombocytopenia: A review. I. Definitions, differential diagnosis, causes, immune thrombocytopenia. Arch Argent Pediatr.119(3):e202-e214. https://doi.org/10.5546/aap.2021.eng.e202.\u003c/li\u003e\n\u003cli\u003eArnold DM, Nazy I, Clare R, Jaffer AM, Aubie B, Li N, Kelton JG (2017) Misdiagnosis of primary immune thrombocytopenia and frequency of bleeding: lessons from the McMaster ITP Registry. Blood Adv.1:2414-2420. https://doi.org/10.1182/bloodadvances.2017010942.\u003c/li\u003e\n\u003cli\u003eHinderlich S, Weidemann W, Yardeni T, Horstkorte R, Huizing M (2015) UDP-GlcNAc 2-Epimerase/ManNAc Kinase (GNE): A master regulator of sialic acid synthesis. Top Curr Chem. 366:97-137. https://doi.org/10.1007/128_2013_464\u003c/li\u003e\n\u003cli\u003eKanamaru Y, Uchiyama T, Kaname T, Yanagi K, Ohara O, Kunishima S, Ishiguro A (2021) ETV6-related thrombocytopenia associated with a transient decrease in von Willebrand factor. Int J Hematol. 114(2):297-300. https://doi.org/10.1007/s12185-021-03136-4\u003c/li\u003e\n\u003cli\u003eSola-Visner M, Saxonhouse MA, Brown RE (2008) Neonatal thrombocytopenia: what we do and don\u0026apos;t know. Early Hum Dev. 84(8):499-506.https:// doi.org/10.1016/j.earlhumdev.2008.06.004\u003c/li\u003e\n\u003cli\u003eDreyfus M, Kaplan C, Verdy E, Schlegel N, Durand-Zaleski I, Tchernia G (1997) Frequency of immune thrombocytopenia in newborns: a prospective study. Immune Thrombocytopenia Working Group. Blood. 89(12):4402-4406. https://doi.org/10.1182/blood.V89.12.4402\u003c/li\u003e\n\u003cli\u003eZieger B, Boeckelmann D, Anani W, Falet H, Zhu J, Glonnegger H, Full H, Andresen F, Erlacher M, Lausch E, Fels S, Strahm B, Lang P, Hoffmeister K (2022) Novel GNE gene variants associated with severe congenital thrombocytopenia and platelet sialylation defect. Thromb Haemost. 122(7):1139-1146. https://doi.org/10.1055/s-0041-1742207\u003c/li\u003e\n\u003cli\u003eEisenberg I, Avidan N, Potikha T, Hochner H, Chen M, Olender T, Barash M, Shemesh M, Sadeh M, Grabov-Nardini G, Shmilevich I, Friedmann A, Karpati G, Bradley G, Baumbach L, Lancet D, Asher WB, Beckmann JS, Argov Z, Mitrani-Rosenbaum S. (2001) The UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase gene is mutated in recessive hereditary inclusion body myopathy. Nat Genet. 29(1):83-7. https://doi:.org/10.1038/ng718. \u003c/li\u003e\n\u003cli\u003eMori-Yoshimura M, Hayashi YK, Yonemoto N, Nakamura H, Murata M, Takeda S, Nishino I, Kimura E (2014) Nationwide patient registry for GNE myopathy in Japan. Orphanet J Rare Dis. 9:150.https:// doi.org/10.1186/s13023-014-0150-4.\u003c/li\u003e\n\u003cli\u003eNishino I, Carrillo-Carrasco N, Argov Z. (2015) GNE myopathy: current update and future therapy. J Neurol Neurosurg Psychiatry. 86(4):385-92. https://doi.org/10.1136/jnnp-2013-307051. \u003c/li\u003e\n\u003cli\u003eArgov Z, Bronstein F, Esposito A, Feinsod-Meiri Y, Florence JM, Fowler E, Greenberg MB, Malkus EC, Rebibo O, Siener CS, Caraco Y, Kolodny EH, Lau HA, Pestronk A, Shieh P, Skrinar AM, Mayhew JE (2017) Characterization of strength and function in ambulatory adults with GNE myopathy. J Clin Neuromuscul Dis. 19(1):19-26. https://doi.org/10.1097/CND.0000000000000181.\u003c/li\u003e\n\u003cli\u003eNemunaitis G, Jay CM, Maples PB, Gahl WA, Huizing M, Yardeni T, Tong AW, Phadke AP, Pappen BO, Bedell C, Allen H, Hernandez C, Templeton NS, Kuhn J, Senzer N, Nemunaitis J (2011) Hereditary inclusion body myopathy: single patient response to intravenous dosing of GNE gene lipoplex. Hum Gene Ther. 22(11):1331-1341. https://doi.org/10.1089/hum.2010.192\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"annals-of-hematology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aohe","sideBox":"Learn more about [Annals of Hematology](http://link.springer.com/journal/277)","snPcode":"277","submissionUrl":"https://submission.nature.com/new-submission/277/3","title":"Annals of Hematology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"GNE, thrombocytopenia, myopathy, NAIT","lastPublishedDoi":"10.21203/rs.3.rs-4708622/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4708622/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003e[Background]\u003c/strong\u003e \u003cem\u003eGNE\u003c/em\u003e encodes a rate-limiting enzyme that regulates the biosynthesis of a sialic acid precursor. As sialic acids are critical for the platelet membrane and muscle fibers, \u003cem\u003eGNE\u003c/em\u003e variants cause \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia and \u003cem\u003eGNE\u003c/em\u003e-related myopathy. Here, we report a neonate with thrombocytopenia that initially met the criteria for neonatal allo-immune thrombocytopenia (NAIT) but was resistant to treatments and then revealed novel biallelic heterozygous \u003cem\u003eGNE\u003c/em\u003e variants without any symptoms of myopathy when diagnosed.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e[Case]\u003c/strong\u003e NAIT was initially diagnosed due to alloantibodies against HPA5 and its mismatch between the patient and his mother. However, intravenous immunoglobulin therapy and platelet transfusions showed minimal improvement in the platelet count. Platelet counts remained around 60 × 10\u003csup\u003e9\u003c/sup\u003e/L, suggesting congenital thrombocytopenia. Gene panel sequencing at the age of 13 identified biallelic pathogenic variants of \u003cem\u003eGNE\u003c/em\u003e. The patient did not exhibit any symptoms of muscular weakness suggesting \u003cem\u003eGNE\u003c/em\u003e-related myopathy.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e[Discussion]\u003c/strong\u003e We demonstrated a \u003cem\u003eGNE\u003c/em\u003e-related thrombocytopenia patient with novel biallelic heterozygous \u003cem\u003eGNE\u003c/em\u003e variants. Clinical trials have involved the use of sialic acids or their precursors, as well as gene therapy, to treat \u003cem\u003eGNE\u003c/em\u003e-related myopathy, which may slow or halt the progression of the disease. Therefore, early diagnosis of this disease may significantly impact its clinical course.\u003c/p\u003e","manuscriptTitle":"Novel biallelic GNE variants identified in a patient with chronic thrombocytopenia without any symptoms of myopathy","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-08-10 12:20:35","doi":"10.21203/rs.3.rs-4708622/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2024-08-29T08:19:58+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"22483922848830663001957764159568415830","date":"2024-07-31T08:33:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2024-07-24T15:03:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"329358241973111618782203356698886718869","date":"2024-07-23T21:33:09+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-07-22T05:09:51+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-07-11T10:40:11+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-07-11T10:40:01+00:00","index":"","fulltext":""},{"type":"submitted","content":"Annals of Hematology","date":"2024-07-09T02:39:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"annals-of-hematology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"aohe","sideBox":"Learn more about [Annals of Hematology](http://link.springer.com/journal/277)","snPcode":"277","submissionUrl":"https://submission.nature.com/new-submission/277/3","title":"Annals of Hematology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"23c83941-2c57-465e-b059-90819555cfde","owner":[],"postedDate":"August 10th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-11-25T15:59:03+00:00","versionOfRecord":{"articleIdentity":"rs-4708622","link":"https://doi.org/10.1007/s00277-024-06104-0","journal":{"identity":"annals-of-hematology","isVorOnly":false,"title":"Annals of Hematology"},"publishedOn":"2024-11-22 15:56:59","publishedOnDateReadable":"November 22nd, 2024"},"versionCreatedAt":"2024-08-10 12:20:35","video":"","vorDoi":"10.1007/s00277-024-06104-0","vorDoiUrl":"https://doi.org/10.1007/s00277-024-06104-0","workflowStages":[]},"version":"v1","identity":"rs-4708622","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4708622","identity":"rs-4708622","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}