{"id":346,"system":{"id":28,"isbt_number":28,"name":"Globoside","symbol":"GLOB","category":"Blood Group System","approved":true,"version":5,"createdAt":"2024-04-29T09:32:32.195Z","updatedAt":"2026-03-12T16:05:38.964Z","description":"The GLOB system was established in 2002 when the P antigen (globoside) was moved from the 209 collection. P is the most common neutral glycosphingolipid in the red cell membrane, belongs to the globoseries and has the following structure: GalNAcb3Gala4Galb4Glcb1 ceramide, also known as globoside (Gb4Cer). The B3GALT3 gene was first reported in 1998 by Amado et al. (1) to be a member of the b1,3-galactosyl­transferase gene family and its product given the name b3Gal-T3. It was later shown by Okajima et al. (2) to possess UDP-N-acetyl­ galactosamine:globotriaosyl­ceramide 3-b-N-acetylgalactosaminyl­transferase or globoside synthase activity and the gene name changed to B3GALNT1 and its product renamed b3GalNAc-T1. This enzyme is responsible for the final step in the synthesis of the P antigen, the transfer of GalNAc to the terminal Gal of the Pk antigen. The final proof of this was the identification in 2002 by Hellberg et al. (3) of critical mutations in the B3GALNT1 gene as the genetic basis of P1k and P2k, the rare globoside-deficient null phenotypes of the GLOB system. Westman et al. (4) showed in 2015 that the same glycosyltransferase is responsible for PX2 antigen synthesis. In addition, 2019 Hagman-Ricci et al. (5) reported that the B antigen can be elongated by β3GalNAc-T1 to form the ExtB antigen. Thus, the system now comprises three antigens.","allele_notes":"","assignees":["Asa Hellberg"]},"gene":{"id":34,"name":"B3GALNT1","isbt_gene":"NG_007854.1","isbt_transcript":"NM_003781.4","isbt_protein":"NP_003772.1","approved":true,"createdAt":"2024-04-29T09:33:12.811Z","updatedAt":"2024-05-06T16:34:47.559Z","version":1,"initiation_codon":null,"stop_codon":null,"entrez_id":26879,"chromosome":"3","hg19_start":160801670,"hg19_end":160823459,"hg38_start":161083883,"hg38_end":161105469,"exon_count":5},"reference_allele":false,"sv_allele":false,"null_allele":true,"mod_allele":false,"partial_allele":false,"weak_allele":false,"el_allele":false,"allele_order":null,"isbt_allele":"GLOB*01N.01","alternate_names":null,"isbt_phenotype":"GLOB:–1 (P–)","isbt_snp":"c.202C>T","table_row_group":null,"notes":null,"approved":true,"comment":null,"deleted":false,"obsolete":false,"provisional":false,"phenotypes":[{"id":2264,"phenotype":"-","approved":true,"predicted":true,"antigen":{"id":85,"isbt_code":"GLOB1","isbt_number":1,"name":"P","display_name":"P","search_terms":["P","028001"],"antigen_order":null,"approved":true,"provisional":false,"compound":false,"multigene":false,"prevalence":"High Frequency","createdAt":"2024-04-29T09:40:45.581Z","updatedAt":"2025-09-24T11:10:15.647Z","version":2},"createdAt":"2024-04-29T09:46:18.857Z","updatedAt":"2024-04-29T09:46:18.857Z","version":1}],"variants":[{"id":798,"input":"NM_003781.4:c.202C>T","note":null,"hgvs_transcript":"NM_003781.4:c.202C>T","exon":"5","intron":null,"rsid":"rs200235398","hgvs_intronic_chr_context":null,"hgvs_intronic_rsg_context":null,"hgvs_refseqgene":"NG_007854.1:g.23820C>T","hgvs_lrg":"LRG_820:g.23820C>T","hgvs_lrg_transcript":"LRG_820t2:c.202C>T","hgvs_predicted_protein":"NP_003772.1:p.(Arg68Ter)","hgvs_genomic_grch37":"NC_000003.11:g.160804341G>A","hgvs_genomic_grch38":"NC_000003.12:g.161086553G>A","grch37_chr":"3","grch37_pos":160804341,"grch37_ref":"G","grch37_alt":"A","grch38_chr":"3","grch38_pos":161086553,"grch38_ref":"G","grch38_alt":"A","freeform_dna_change":null,"freeform_exon":null,"freeform_intron":null,"freeform_predicted_protein":null,"alternative_splicing":false,"gene_name":"B3GALNT1","approved":true,"gnomad_all":0.00008487323531816931,"gnomad_afr":0,"gnomad_amr":0,"gnomad_asj":0,"gnomad_eas":0.000022277668864729994,"gnomad_fin":0.0012650715312050977,"gnomad_nfe":0.00003643944273075489,"gnomad_remaining":0.00009598464245720684,"gnomad_sas":0.00005490282200505106,"gnomad_mid":0.0001649620587264929,"gnomad_ami":0,"createdAt":"2024-04-29T10:00:22.603Z","updatedAt":"2026-04-02T20:29:08.406Z","version":4}],"genbanks":[{"id":751,"accession":"AF494103","definition":"Homo sapiens mutant globoside synthase gene, complete cds","createdAt":"2024-09-29T14:39:45.483Z","updatedAt":"2024-09-29T14:39:45.483Z","version":1}],"publications":[{"id":255,"identifier":"12023287","citation":"Hellberg A, Poole J, Olsson ML. Molecular basis of the globoside-deficient P(k) blood group phenotype. Identification of four inactivating mutations in the UDP-N-acetylgalactosamine: globotriaosylceramide 3-beta-N-acetylgalactosaminyltransferase gene. J Biol Chem. 2002 Aug;33(277):29455-9.","type":"pmid","createdAt":"2024-09-29T12:17:19.220Z","updatedAt":"2024-09-29T12:17:19.220Z","version":1}],"createdBy":{"username":"Nick Gleadall"},"updatedBy":{"username":"Nick Gleadall"},"createdAt":"2024-04-29T09:38:13.694Z","updatedAt":"2026-04-02T20:29:08.477Z","version":2}