{"id":894,"system":{"id":38,"isbt_number":38,"name":"SID","symbol":"SID","category":"Blood Group System","approved":true,"version":2,"createdAt":"2024-04-29T09:32:37.523Z","updatedAt":"2025-09-24T11:11:42.005Z","description":"Sda or SID1, the only antigen of the SID blood group system, was discovered in 1967. About 90% of the European population carries the antigen on their red blood cells (RBCs). Although there are 10% missing the antigen on their RBCs only 4% lack expression in all tissues and fluids and thereby have the true null phenotype, Sd(a‒). The antibodies against Sda form a characteristic RBC agglutination pattern of small agglutinates surrounded by numerous free cells. The B4GALNT2-encoded transferase synthesizes the Sda antigen by the addition of an N-acetylgalactosamine to its precursors, which can be glycans on glycoproteins or glycosphingolipid conjugates (in the neolacto synthetic pathway). Alterations in B4GALNT2 that abolish transferase activity cause the Sd(a‒) phenotype. Another phenotype, the rare Cad or Sd(a++) or Super-SID, describes RBCs that are more strongly agglutinated by anti-Sda. If this trait is quantitative or qualitative is to date not fully understood, nor is its genetic background. Differences from reference allele SID*01 (accession number AJ517770) are given in the table.","allele_notes":"","assignees":["Asa Hellberg"]},"gene":{"id":44,"name":"B4GALNT2","isbt_gene":null,"isbt_transcript":"NM_153446.3","isbt_protein":"NP_703147.2","approved":true,"createdAt":"2024-04-29T09:33:22.524Z","updatedAt":"2024-05-06T16:34:47.874Z","version":1,"initiation_codon":null,"stop_codon":null,"entrez_id":124872,"chromosome":"17","hg19_start":47209822,"hg19_end":47247351,"hg38_start":49120347,"hg38_end":49176840,"exon_count":12},"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":"SID*01N.03","alternate_names":null,"isbt_phenotype":"Sd(a-)","isbt_snp":"c.1307A>G","table_row_group":null,"notes":null,"approved":true,"comment":null,"deleted":false,"obsolete":false,"provisional":false,"phenotypes":[{"id":8148,"phenotype":"-","approved":true,"predicted":true,"antigen":{"id":202,"isbt_code":"SID1","isbt_number":1,"name":"SID","display_name":"SID","search_terms":["SID","038001"],"antigen_order":null,"approved":true,"provisional":false,"compound":false,"multigene":false,"prevalence":"High Frequency","createdAt":"2024-04-29T09:40:56.325Z","updatedAt":"2025-09-24T11:11:42.141Z","version":2},"createdAt":"2024-04-29T09:59:19.368Z","updatedAt":"2024-04-29T09:59:19.368Z","version":1}],"variants":[{"id":685,"input":"NM_153446.3:c.1307A>G","note":null,"hgvs_transcript":"NM_153446.3:c.1307A>G","exon":"10","intron":null,"rsid":"rs148441237","hgvs_intronic_chr_context":null,"hgvs_intronic_rsg_context":null,"hgvs_refseqgene":null,"hgvs_lrg":null,"hgvs_lrg_transcript":null,"hgvs_predicted_protein":"NP_703147.2:p.(Gln436Arg)","hgvs_genomic_grch37":"NC_000017.10:g.47246074A>G","hgvs_genomic_grch38":"NC_000017.11:g.49168712A>G","grch37_chr":"17","grch37_pos":47246074,"grch37_ref":"A","grch37_alt":"G","grch38_chr":"17","grch38_pos":49168712,"grch38_ref":"A","grch38_alt":"G","freeform_dna_change":null,"freeform_exon":null,"freeform_intron":null,"freeform_predicted_protein":null,"alternative_splicing":false,"gene_name":"B4GALNT2","approved":true,"gnomad_all":0.00020569757499907065,"gnomad_afr":0.0040393537034074545,"gnomad_amr":0.00013330667199893355,"gnomad_asj":0,"gnomad_eas":0.00002228064702998975,"gnomad_fin":0,"gnomad_nfe":0.00000847450445335209,"gnomad_remaining":0.00015998464147441846,"gnomad_sas":0,"gnomad_mid":0,"gnomad_ami":0,"createdAt":"2024-04-29T10:00:16.373Z","updatedAt":"2026-04-02T20:08:17.943Z","version":4}],"genbanks":[{"id":805,"accession":"MK765048","definition":"Homo sapiens B4GALNT2 (B4GALNT2) gene, exon 10 and partial cds","createdAt":"2024-09-29T14:40:17.847Z","updatedAt":"2024-09-29T14:40:17.847Z","version":1}],"publications":[{"id":580,"identifier":"31367682","citation":"Stenfelt L, Hellberg Å, Möller M, Thornton N, Larson G, Olsson ML. Missense mutations in the C-terminal portion of the B4GALNT2-encoded glycosyltransferase underlying the Sd(a-) phenotype. Biochem Biophys Rep. 2019 Sep;(19):100659.","type":"pmid","createdAt":"2024-09-29T12:17:33.393Z","updatedAt":"2024-09-29T12:17:33.393Z","version":1}],"createdBy":{"username":"Nick Gleadall"},"updatedBy":{"username":"Nick Gleadall"},"createdAt":"2024-04-29T09:39:10.013Z","updatedAt":"2026-04-02T20:08:18.015Z","version":2}