{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T04:55:41Z","timestamp":1790916941834,"version":"4.1.0"},"reference-count":55,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T00:00:00Z","timestamp":1790899200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>ABO subtypes are characterized by attenuated antigen expression, rendering them susceptible to serological misclassification and posing substantial risks to transfusion safety. Splice-site variants represent one of the mechanisms underlying ABO subtype formation; however, previous mechanistic investigations have predominantly focused on the 5\u2032 splice-site(5\u2032SS), leaving the functional consequences of 3\u2032 splice-site (3\u2032SS) variants largely unexplored.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>\n                      Serological phenotyping of a proband with ABO grouping discrepancy was performed using tube agglutination, microcolumn gel agglutination, and absorption-elution assays. Genotyping was resolved by long-range PCR coupled with Nanopore sequencing. The splicing impact of this novel variant and two previously reported variants, c.29-3C&amp;gt;G and c.29-10T&amp;gt;A, was predicted\n                      <jats:italic>in silico<\/jats:italic>\n                      and validated by\n                      <jats:italic>in vitro<\/jats:italic>\n                      minigene assay. Computational saturation mutagenesis was further deployed to systematically delineate a preliminary framework of regulatory principles governing 3\u2032SS variation.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>\n                      A novel 3\u2032SS variant, c.29-2A&amp;gt;G, was identified in an\n                      <jats:italic>ABO*A1.02<\/jats:italic>\n                      background in a proband with an A\n                      <jats:sub>el<\/jats:sub>\n                      phenotype. This novel variant and two previously reported variants disrupted the canonical 3\u2019SS of intron 1, converging on exon 2 skipping as the predominant aberrant splicing event. Additionally, c.29-10T&amp;gt;A activated a cryptic acceptor site, generating a secondary transcript with an 8-bp intronic retention. All aberrant transcripts disrupt the open reading frame and introduce premature termination codons. Through computational saturation mutagenesis, we further established an initial position- and base-dependent risk stratification model for 3\u2032SS variants.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>\n                      This study provides the first direct mechanistic evidence linking\n                      <jats:italic>ABO<\/jats:italic>\n                      3\u2032SS variants to subtype pathogenesis, demonstrating that exon 2 skipping constitutes a shared molecular lesion across intron 1 3\u2032SS variants, ultimately leading to attenuated blood group antigen expression. The preliminary computationally derived risk stratification framework established herein offers a clinically valuable reference for interpreting 3\u2032SS variants, with implications that extend beyond blood group genetics to the broader landscape of splicing-mediated human diseases.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1959480","type":"journal-article","created":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T04:36:00Z","timestamp":1790915760000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Three ABO 3\u2032 splice-site variants including a novel one converge on a common splicing defect to attenuate blood group antigen expression"],"prefix":"10.3389","volume":"17","author":[{"given":"Hongli","family":"Guan","sequence":"first","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yalan","family":"Yang","sequence":"additional","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jian","family":"Li","sequence":"additional","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huan","family":"Zhang","sequence":"additional","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xue","family":"Chen","sequence":"additional","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jialiang","family":"Gao","sequence":"additional","affiliation":[{"name":"Blood Grouping Reference Laboratory, Chengdu Blood Center","place":["Chengdu, Sichuan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,10,2]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1556-4029.2006.00058.x","article-title":"Minisequencing-based genotyping of Duffy and ABO blood groups for forensic purposes","volume":"51","author":"Ferri","year":"2006","journal-title":"J Forensic Sci"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.2152\/jmi.55.174","article-title":"Biological and clinical aspects of ABO blood group system","volume":"55","author":"Hosoi","year":"2008","journal-title":"J Med Invest JMI"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1097\/MOH.0b013e3282e9a576","article-title":"Immune hemolysis following ABO-mismatched stem cell or solid organ transplantation","volume":"14","author":"Yazer","year":"2007","journal-title":"Curr Opin Hematol"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1016\/S0021-9258(19)84610-0","article-title":"Glycosyltransferases. 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