Two GWAS of the sugar chains attached to antibody molecules found the same glycosyltransferase genes twice, plus immune-related loci already linked to autoimmune disease and blood cancers.
Antibodies of the IgG class — the most abundant antibody in blood — carry a chain of sugar molecules (a glycan) attached to a specific site on the protein. This glycan is not a passive decoration: it shapes how strongly the antibody's Fc region binds to immune receptors, which in turn shapes how effectively the antibody triggers an immune response. IgG glycosylation is the study of how that sugar chain varies between people, and how much of that variation is genetic.
Lauc et al. 2013 measured IgG glycans in 2,247 people across four European populations, replicating in 1,848 more using a different measurement platform. The study found 9 genome-wide significant loci: four in known glycosyltransferase genes — the enzymes that physically attach sugar units to the glycan — and five in genes never before linked to protein glycosylation, most of which were already strongly associated with autoimmune disease and blood cancers. In follow-up experiments, mice bred to lack one copy of Ikzf1 showed the same glycosylation changes the human GWAS had found, and IgG glycan measurements tied to IKZF1 distinguished lupus patients from healthy controls with strong accuracy in a small case-control comparison. This page's own variants match five of that paper's nine named loci directly: rs11710456 and rs7652995 in ST6GAL1, rs6583437 in IKZF1, rs2186369 in SMARCB1, and rs4930561 in SUV420H1.
Wahl et al. 2018 ran a follow-up study in 1,823 people, replicated in 1,836 more, and confirmed the same glycosyltransferase genes Lauc's earlier study had found — ST6GAL1, B4GALT1, FUT8, and MGAT3 — while adding a novel locus at RUNX3, a gene already known for its role in immune cell differentiation, tied here to reduced galactosylation of the glycan. This page's own variants match this paper's FUT8, ST6GAL1, and B4GALT1 loci directly, with FUT8 alone represented by eight of this page's variants, including rs10134589 and rs7153297.
The same handful of glycosyltransferase genes turning up independently in both studies — 5 years apart, in different cohorts — is a stronger form of evidence than either finding alone.
Positions joined since this page was written
What this is The text above discusses the variants this page was written around. Since then the catalogue has joined 2 more positions to it, by shared trait or shared paper. They are listed here by the paper each came from; the text does not describe them, and each variant page carries that study's own record.
Wahl A et al. 2018, Frontiers in immunology rs73396548 (CHCHD10), rs11622829 (FUT8) — PMID:29535710
IgG glycan structure is measured directly with mass spectrometry or chromatography in a research setting, not with any routine clinical test, and nothing on this page diagnoses an autoimmune disease or cancer. Several of these genes are separately associated with autoimmune conditions and blood cancers in other studies — that is a research finding about shared biology, not a claim that a variant here predicts any specific disease.
IgG glycosylation is an active research area precisely because it sits upstream of immune function generally, touching conditions as different as lupus and leukemia. None of that makes this page, or any variant on it, a diagnostic or predictive tool for those conditions.
What a 23andMe/AncestryDNA export or raw VCF can and can't tell you about IgG Glycosylation comes down to these specific, well-studied positions — not a diagnosis. 28 positions are linked to this page; the ones this page's own text discusses are shown first.
The studies behind these variants recruited participants from different ancestries — a result found in one population doesn't always transfer to another. Based on 28 of 28 linked studies with a resolved discovery ancestry.
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IgG Glycosylation. MyGeneLog™. https://www.mygenelog.com/conditions/igg-glycosylation
IgG glycosylation refers to the sugar chain (glycan) attached to antibody molecules of the IgG class, which shapes how strongly the antibody triggers an immune response. This page covers genetic variants that influence how that sugar chain varies between people.
Both independently found the same core glycosyltransferase genes — ST6GAL1, B4GALT1, FUT8, and MGAT3 — plus additional loci in each study not found in the other, several of them already linked to autoimmune disease and blood cancers.
No. Several of these genes are separately associated with autoimmune conditions and blood cancers in other research, but that reflects shared biology, not a diagnostic or predictive claim about any variant on this page.
With mass spectrometry or liquid chromatography in a research setting — not with any test available through routine clinical care.
Free to reuse. This page's text is original writing from freely-available research, licensed CC BY 4.0 — reuse it, including commercially, with attribution to MyGeneLog™. It's general research-derived information, not medical advice or a diagnosis — see Terms of Use.