{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T16:21:33Z","timestamp":1791130893408,"version":"4.1.0"},"reference-count":39,"publisher":"Springer Science and Business Media LLC","issue":"2","license":[{"start":{"date-parts":[[2021,12,17]],"date-time":"2021-12-17T00:00:00Z","timestamp":1639699200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2021,12,17]],"date-time":"2021-12-17T00:00:00Z","timestamp":1639699200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100016062","name":"Metakids","doi-asserted-by":"crossref","award":["2018-081"],"award-info":[{"award-number":["2018-081"]}],"id":[{"id":"10.13039\/100016062","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Acta Neuropathol"],"published-print":{"date-parts":[[2022,2]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Nucleotide metabolism is a complex pathway regulating crucial cellular processes such as nucleic acid synthesis, DNA repair and proliferation. This study shows that impairment of the biosynthesis of one of the building blocks of DNA, dTTP, causes a severe, early-onset neurodegenerative disease. Here, we describe two unrelated children with bi-allelic variants in <jats:italic>DTYMK,<\/jats:italic> encoding dTMPK, which catalyzes the penultimate step in dTTP biosynthesis. The affected children show severe microcephaly and growth retardation with minimal neurodevelopment. Brain imaging revealed severe cerebral atrophy and disappearance of the basal ganglia. In cells of affected individuals, dTMPK enzyme activity was minimal, along with impaired DNA replication. In addition, we generated <jats:italic>dtymk<\/jats:italic> mutant zebrafish that replicate this phenotype of microcephaly, neuronal cell death and early lethality. An increase of ribonucleotide incorporation in the genome as well as impaired responses to DNA damage were observed in <jats:italic>dtymk<\/jats:italic> mutant zebrafish, providing novel pathophysiological insights. It is highly remarkable that this deficiency is viable as an essential component for DNA cannot be generated, since the metabolic pathway for dTTP synthesis is completely blocked. In summary, by combining genetic and biochemical approaches in multiple models we identified loss-of-function of <jats:italic>DTYMK<\/jats:italic> as the cause of a severe postnatal neurodegenerative disease and highlight the essential nature of dTTP synthesis in the maintenance of genome stability and neuronal survival.<\/jats:p>","DOI":"10.1007\/s00401-021-02394-0","type":"journal-article","created":{"date-parts":[[2021,12,17]],"date-time":"2021-12-17T04:26:23Z","timestamp":1639715183000},"page":"245-262","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["DTYMK is essential for genome integrity and neuronal survival"],"prefix":"10.1007","volume":"143","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1830-8858","authenticated-orcid":false,"given":"Jo M.","family":"Vanoevelen","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J\u00f6rgen","family":"Bierau","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janine C.","family":"Grashorn","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ellen","family":"Lambrichs","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erik-Jan","family":"Kamsteeg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Levinus A.","family":"Bok","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ron A.","family":"Wevers","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marjo S.","family":"van der Knaap","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marianna","family":"Bugiani","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junmei Hu","family":"Frisk","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rita","family":"Colnaghi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"O\u2019Driscoll","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Debby M. E. I.","family":"Hellebrekers","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Richard","family":"Rodenburg","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlos R.","family":"Ferreira","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Han G.","family":"Brunner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arthur","family":"van den Wijngaard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ghada M. H.","family":"Abdel-Salam","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liya","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Constance T. R. M.","family":"Stumpel","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2021,12,17]]},"reference":[{"key":"2394_CR1","doi-asserted-by":"publisher","first-page":"124","DOI":"10.1002\/ajmg.c.31397","volume":"66C","author":"D Alcantara","year":"2014","unstructured":"Alcantara D, O\u2019Driscoll M (2014) Congenital microcephaly. Am J Med Genet C Semin Med Genet 66C:124\u2013139","journal-title":"Am J Med Genet C Semin Med Genet"},{"key":"2394_CR2","doi-asserted-by":"publisher","first-page":"444","DOI":"10.1136\/jmg.2005.031880","volume":"43","author":"M Ali","year":"2006","unstructured":"Ali M, Highet LJ, Lacombe D et al (2006) A second locus for Aicardi-Goutieres syndrome at chromosome 13q14-21. J Med Genet 43:444\u2013450","journal-title":"J Med Genet"},{"key":"2394_CR3","doi-asserted-by":"publisher","first-page":"155","DOI":"10.1016\/0163-7258(95)00015-9","volume":"67","author":"ES Arn\u00e9r","year":"1995","unstructured":"Arn\u00e9r ES, Eriksson S (1995) Mammalian deoxyribonucleoside kinases. Pharmacol Ther 67:155\u2013186","journal-title":"Pharmacol Ther"},{"key":"2394_CR4","doi-asserted-by":"publisher","first-page":"776","DOI":"10.1038\/ng2040","volume":"39","author":"A Bourdon","year":"2007","unstructured":"Bourdon A, Minai L, Serr V et al (2007) Mutation of RRM2B, encoding p53-controlled ribonucleotide reductase (p53R2), causes severe mitochondrial DNA depletion. Nat Genet 39:776\u2013780","journal-title":"Nat Genet"},{"key":"2394_CR5","doi-asserted-by":"publisher","first-page":"771","DOI":"10.1046\/j.1365-2958.2003.03717.x","volume":"50","author":"C Carnrot","year":"2003","unstructured":"Carnrot C, Wehelie R, Eriksson S et al (2003) Molecular characterization of thymidine kinase from Ureaplasma urealyticum: nucleoside analogues as potent inhibitors of mycoplasma growth. Mol Microbiol 50:771\u2013780","journal-title":"Mol Microbiol"},{"key":"2394_CR6","doi-asserted-by":"publisher","first-page":"434","DOI":"10.1016\/j.tibs.2016.02.005","volume":"41","author":"SM Cerritelli","year":"2016","unstructured":"Cerritelli SM, Crouch RJ (2016) The balancing act of ribonucleotides in DNA. Trends Biochem Sci 41:434\u2013445","journal-title":"Trends Biochem Sci"},{"key":"2394_CR7","doi-asserted-by":"publisher","first-page":"679","DOI":"10.1111\/j.1365-2443.2008.01197.x","volume":"13","author":"YL Chen","year":"2008","unstructured":"Chen YL, Lin DW, Chang ZF (2008) Identification of a putative human mitochondrial thymidine monophosphate kinase associated with monocytic\/macrophage terminal differentiation. Genes Cells 13:679\u2013689","journal-title":"Genes Cells"},{"key":"2394_CR8","doi-asserted-by":"publisher","first-page":"910","DOI":"10.1038\/ng1842","volume":"38","author":"YJ Crow","year":"2006","unstructured":"Crow YJ, Leitch A, Hayward BE et al (2006) Mutations in genes encoding ribonuclease H2 subunits cause Aicardi-Gouti\u00e8res syndrome and mimic congenital viral brain infection. Nat Genet 38:910\u2013916","journal-title":"Nat Genet"},{"key":"2394_CR9","doi-asserted-by":"publisher","first-page":"1104","DOI":"10.1111\/j.1742-4658.2008.06853.x","volume":"276","author":"M Frangini","year":"2009","unstructured":"Frangini M, Rampazzo C, Franzolin E, Lara MC, Vil\u00e0 MR, Mart\u00ed R et al (2009) Unchanged thymidine triphosphate pools and thymidine metabolism in two lines of thymidine kinase 2-mutated fibroblasts. FEBS J 276:1104\u20131113","journal-title":"FEBS J"},{"issue":"5","key":"2394_CR10","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0098186","volume":"9","author":"JA Gagnon","year":"2014","unstructured":"Gagnon JA, Valen E, Thyme SB et al (2014) Efficient mutagenesis by Cas9 protein-mediated oligonucleotide insertion and large-scale assessment of single-guide RNAs. PLoS ONE 9(5):e98186","journal-title":"PLoS ONE"},{"key":"2394_CR11","doi-asserted-by":"publisher","first-page":"135","DOI":"10.1038\/ng896","volume":"31","author":"G Golling","year":"2002","unstructured":"Golling G, Amsterdam A, Sun Z et al (2002) Insertional mutagenesis in zebrafish rapidly identifies genes essential for early vertebrate development. Nat Genet 31:135\u2013140","journal-title":"Nat Genet"},{"key":"2394_CR12","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pgen.1002035","volume":"7","author":"E Gonz\u00e1lez-Vioque","year":"2011","unstructured":"Gonz\u00e1lez-Vioque E, Torres-Torronteras J, Andreu AL et al (2011) Limited dCTP availability accounts for mitochondrial DNA depletion in mitochondrial neurogastrointestinal encephalomyopathy (MNGIE). PLoS Genet 7:e1002035","journal-title":"PLoS Genet"},{"key":"2394_CR13","doi-asserted-by":"publisher","first-page":"461","DOI":"10.1089\/dna.1994.13.461","volume":"13","author":"SH Huang","year":"1994","unstructured":"Huang SH, Tang A, Drisco B, Zhang SQ et al (1994) Human dTMP kinase: gene expression and enzymatic activity coinciding with cell cycle progression and cell growth. DNA Cell Biol 13:461\u2013471","journal-title":"DNA Cell Biol"},{"key":"2394_CR14","doi-asserted-by":"publisher","first-page":"1534","DOI":"10.1093\/brain\/awt054","volume":"136","author":"SH Kevelam","year":"2013","unstructured":"Kevelam SH, Bugiani M, Salomons GS, Feigenbaum A, Blaser S, Prasad C et al (2013) Exome sequencing reveals mutated SLC19A3 in patients with an early-infantile, lethal encephalopathy. Brain 136:1534\u20131543","journal-title":"Brain"},{"key":"2394_CR15","doi-asserted-by":"publisher","first-page":"279","DOI":"10.1093\/brain\/aww300","volume":"140","author":"J Koch","year":"2017","unstructured":"Koch J, Mayr JA, Alhaddad B, Rauscher C, Bierau J, Kovacs-Nagy R et al (2017) CAD mutations and uridine-responsive epileptic encephalopathy. Brain 140:279\u2013286","journal-title":"Brain"},{"key":"2394_CR16","doi-asserted-by":"publisher","first-page":"W272","DOI":"10.1093\/nar\/gkw398","volume":"44","author":"K Labun","year":"2016","unstructured":"Labun K, Montague TG, Gagnon JA et al (2016) CHOPCHOP v2: a web tool for the next generation of CRISPR genome engineering. Nucleic Acids Res 44:W272\u2013W276","journal-title":"Nucleic Acids Res"},{"key":"2394_CR17","doi-asserted-by":"publisher","first-page":"93","DOI":"10.1016\/j.cca.2019.06.028","volume":"496","author":"CW Lam","year":"2019","unstructured":"Lam CW, Yeung WL, Ling TK et al (2019) Deoxythymidylate kinase, DTYMK, is a novel gene for mitochondrial DNA depletion syndrome. Clin Chim Acta 496:93\u201399","journal-title":"Clin Chim Acta"},{"key":"2394_CR18","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.aquaculture.2007.04.077","volume":"269","author":"C Lawrence","year":"2007","unstructured":"Lawrence C (2007) The husbandry of zebrafish (Danio rerio): a review. Aquaculture 269:1\u201320","journal-title":"Aquaculture"},{"key":"2394_CR19","doi-asserted-by":"publisher","first-page":"29801","DOI":"10.1074\/jbc.M115.695254","volume":"290","author":"LA Lindsey-Boltz","year":"2015","unstructured":"Lindsey-Boltz LA, Kemp MG, Hu J et al (2015) Analysis of ribonucleotide removal from DNA by human nucleotide excision repair. J Biol Chem 290:29801\u201329807","journal-title":"J Biol Chem"},{"key":"2394_CR20","doi-asserted-by":"publisher","first-page":"5364","DOI":"10.1021\/ja990592p","volume":"121","author":"YF Li","year":"1999","unstructured":"Li YF, Breaker RR (1999) Kinetics of RNA degradation by specific base catalysts of transesterification. J Am Chem Soc 121:5364\u20135372","journal-title":"J Am Chem Soc"},{"key":"2394_CR21","doi-asserted-by":"publisher","first-page":"1373","DOI":"10.1016\/j.bpj.2017.07.013","volume":"113","author":"A Meroni","year":"2017","unstructured":"Meroni A, Mentegari E, Crespan E et al (2017) The incorporation of ribonucleotides induces structural and conformational changes in DNA. Biophys J 113:1373\u20131382","journal-title":"Biophys J"},{"key":"2394_CR22","doi-asserted-by":"publisher","first-page":"3050","DOI":"10.1093\/hmg\/ddv057","volume":"24","author":"BG Ng","year":"2015","unstructured":"Ng BG, Wolfe LA, Ichikawa M, Markello T, He M, Tifft CJ et al (2015) Biallelic mutations in CAD, impair de novo pyrimidine biosynthesis and decrease glycosylation precursors. Hum Mol Genet 24:3050\u20133057","journal-title":"Hum Mol Genet"},{"key":"2394_CR23","doi-asserted-by":"publisher","first-page":"774","DOI":"10.1038\/nchembio.424","volume":"6","author":"SA Nick McElhinny","year":"2010","unstructured":"Nick McElhinny SA, Kumar D, Clark AB, Watt DL, Watts BE, Lundstr\u00f6m E-B et al (2010) Genome instability due to ribonucleotide incorporation into DNA. Nat Chem Biol 6:774\u2013781","journal-title":"Nat Chem Biol"},{"key":"2394_CR24","doi-asserted-by":"publisher","first-page":"689","DOI":"10.1126\/science.283.5402.689","volume":"283","author":"I Nishino","year":"1999","unstructured":"Nishino I, Spinazzola A, Hirano M (1999) Thymidine phosphorylase gene mutations in MNGIE, a human mitochondrial disorder. Science 283:689\u2013692","journal-title":"Science"},{"key":"2394_CR25","doi-asserted-by":"publisher","first-page":"995","DOI":"10.1007\/BF01920108","volume":"52","author":"FJ Oliver","year":"1996","unstructured":"Oliver FJ, Collins MK, L\u00f3pez-Rivas A (1996) dNTP pool imbalance as a signal to initiate apoptosis. Experientia 52:995\u20131000","journal-title":"Experientia"},{"key":"2394_CR26","doi-asserted-by":"publisher","first-page":"629","DOI":"10.1016\/S0969-2126(00)00149-0","volume":"8","author":"N Ostermann","year":"2000","unstructured":"Ostermann N, Schlichting I, Brundiers R, Konrad M, Reinstein J, Veit T et al (2000) Insights into the phosphoryltransfer mechanism of human thymidylate kinase gained from crystal structures of enzyme complexes along the reaction coordinate. Structure 8:629\u2013642","journal-title":"Structure"},{"key":"2394_CR27","first-page":"10338","volume":"43","author":"JJ Rahn","year":"2015","unstructured":"Rahn JJ, Bestman JE, Stackley KD, Chan SS (2015) Zebrafish lacking functional DNA polymerase gamma survive to juvenile stage, despite rapid and sustained mitochondrial DNA depletion, altered energetics and growth. Nucleic Acids Res 43:10338\u201310352","journal-title":"Nucleic Acids Res"},{"key":"2394_CR28","doi-asserted-by":"publisher","first-page":"1008","DOI":"10.1016\/j.cell.2012.04.011","volume":"149","author":"MA Reijns","year":"2012","unstructured":"Reijns MA, Rabe B, Rigby RE et al (2012) Enzymatic removal of ribonucleotides from DNA is essential for mammalian genome integrity and development. Cell 149:1008\u20131022","journal-title":"Cell"},{"key":"2394_CR29","doi-asserted-by":"publisher","first-page":"283","DOI":"10.1007\/s10545-010-9081-y","volume":"34","author":"RJT Rodenburg","year":"2011","unstructured":"Rodenburg RJT (2011) Biochemical diagnosis of mitochondrial disorders. J Inherit Metab Dis 34:283\u2013292","journal-title":"J Inherit Metab Dis"},{"key":"2394_CR30","doi-asserted-by":"publisher","first-page":"169","DOI":"10.1016\/j.ymgme.2008.07.007","volume":"95","author":"A Saada","year":"2008","unstructured":"Saada A (2008) Mitochondrial deoxyribonucleotide pools in deoxyguanosine kinase deficiency. Mol Genet Metab 95:169\u2013173","journal-title":"Mol Genet Metab"},{"key":"2394_CR31","doi-asserted-by":"publisher","DOI":"10.1101\/pdb.prot4027","author":"J Sambrook","year":"2016","unstructured":"Sambrook J, Russell DW (2016) Alkaline agarose gel electrophoresis. CSH Protoc. https:\/\/doi.org\/10.1101\/pdb.prot4027","journal-title":"CSH Protoc"},{"key":"2394_CR32","doi-asserted-by":"publisher","first-page":"503","DOI":"10.1016\/j.ajhg.2017.08.014","volume":"101","author":"P Stankiewicz","year":"2017","unstructured":"Stankiewicz P, Khan TN, Szafranski P et al (2017) Haploinsufficiency of the chromatin remodeler BPTF causes syndromic developmental and speech delay, postnatal microcephaly, and dysmorphic features. Am J Hum Genet 101:503\u2013515","journal-title":"Am J Hum Genet"},{"key":"2394_CR33","doi-asserted-by":"publisher","first-page":"583","DOI":"10.1089\/zeb.2014.1047","volume":"11","author":"JC Talbot","year":"2014","unstructured":"Talbot JC, Amacher SL (2014) A streamlined CRISPR pipeline to reliably generate zebrafish frameshifting alleles. Zebrafish 11:583\u2013585","journal-title":"Zebrafish"},{"key":"2394_CR34","doi-asserted-by":"publisher","first-page":"1135","DOI":"10.1016\/j.celrep.2018.10.019","volume":"25","author":"R Uehara","year":"2018","unstructured":"Uehara R, Cerritelli SM, Hasin N et al (2018) Two RNase H2 mutants with differential rNMP processing activity reveal a threshold of ribonucleotide tolerance for embryonic development. Cell Rep 25:1135\u20131145","journal-title":"Cell Rep"},{"key":"2394_CR35","doi-asserted-by":"publisher","first-page":"548","DOI":"10.1186\/1471-2105-11-548","volume":"11","author":"H Venselaar","year":"2010","unstructured":"Venselaar H, Te Beek TAH, Kuipers RKP, Hekkelman ML, Vriend G (2010) Protein structure analysis of mutations causing inheritable diseases. An e-Science approach with life scientist friendly interfaces. BMC Bioinform 11:548","journal-title":"BMC Bioinform"},{"key":"2394_CR36","doi-asserted-by":"publisher","first-page":"1340","DOI":"10.4161\/15476286.2014.992283","volume":"11","author":"BD Wallace","year":"2014","unstructured":"Wallace BD, Williams RS (2014) Ribonucleotide triggered DNA damage and RNA-DNA damage responses. RNA Biol 11:1340\u20131346","journal-title":"RNA Biol"},{"key":"2394_CR37","doi-asserted-by":"publisher","first-page":"1983","DOI":"10.1111\/j.1742-4658.2007.05742.x","volume":"274","author":"L Wang","year":"2007","unstructured":"Wang L (2007) The role of Ureaplasma nucleoside monophosphate kinases in the synthesis of nucleoside triphosphates. FEBS J 274:1983\u20131990","journal-title":"FEBS J"},{"key":"2394_CR38","doi-asserted-by":"publisher","first-page":"1827","DOI":"10.1534\/genetics.105.041608","volume":"170","author":"GB Willer","year":"2005","unstructured":"Willer GB, Lee VM, Gregg RG et al (2005) Analysis of the Zebrafish perplexed mutation reveals tissue-specific roles for de novo pyrimidine synthesis during development. Genetics 170:1827\u20131837","journal-title":"Genetics"},{"key":"2394_CR39","doi-asserted-by":"publisher","first-page":"1563","DOI":"10.1074\/jbc.M707997200","volume":"283","author":"Y Xu","year":"2008","unstructured":"Xu Y, Johansson M, Karlsson A (2008) Human UMP-CMP kinase 2, a novel nucleoside monophosphate kinase localized in mitochondria. J Biol Chem 283:1563\u20131571","journal-title":"J Biol Chem"}],"container-title":["Acta Neuropathologica"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s00401-021-02394-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1007\/s00401-021-02394-0\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s00401-021-02394-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,1,8]],"date-time":"2022-01-08T11:03:58Z","timestamp":1641639838000},"score":1,"resource":{"primary":{"URL":"https:\/\/link.springer.com\/10.1007\/s00401-021-02394-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,17]]},"references-count":39,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2022,2]]}},"alternative-id":["2394"],"URL":"https:\/\/doi.org\/10.1007\/s00401-021-02394-0","relation":{},"ISSN":["0001-6322","1432-0533"],"issn-type":[{"value":"0001-6322","type":"print"},{"value":"1432-0533","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,17]]},"assertion":[{"value":"8 June 2021","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"3 December 2021","order":2,"name":"revised","label":"Revised","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"3 December 2021","order":3,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"17 December 2021","order":4,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Conflict of interest"}}]}}