rs11264799 — FCRL3

FCRL3 rs11264799 — An Upstream Switch in B-Cell Regulatory Tone

The FCRL3¹¹ FCRL3
Fc receptor-like 3; expressed at high levels on B cells and regulatory T cells, where it modulates activation thresholds and autoantibody production through immunoreceptor tyrosine-based inhibitory and activation motifs (ITIMs and ITAMs) gene sits on chromosome 1q23, a region densely populated with immune receptor genes. rs11264799 lies approximately 59 bp from the well-studied rs7528684 promoter variant, placing it squarely in the upstream regulatory landscape of FCRL3. The variant itself does not change the FCRL3 protein — it is classified as an upstream transcript variant — but it exerts a measurable influence on how much FCRL3 is produced in immune cells.

FCRL3 is on the minus strand of chromosome 1; the alleles reported in genome files (C and T) are plus-strand notation. The C allele is the GRCh38 reference and the more common allele globally (~73%); the T allele is the minor variant (~27%) that carries the eQTL signal.

The Mechanism

rs11264799 has been identified as a strong expression quantitative trait locus (eQTL)²² strong expression quantitative trait locus (eQTL)
eQTLs are genetic variants that influence the amount of RNA or protein produced by a nearby gene; they act as natural experiments showing how subtle regulatory changes alter gene dosage in human tissues for FCRL3. In B cells and regulatory T cells, higher FCRL3 expression alters the balance between activation and inhibition: more surface FCRL3 can either amplify or dampen B cell receptor signals depending on the cellular context. The T allele's eQTL effect on FCRL3 expression in lymphoid tissue explains why it has been repeatedly captured in genetic studies of conditions where B cell tolerance is central — IgA nephropathy, autoimmune thyroid disease, and inflammatory arthritis — even though the individual SNP associations are smaller and less consistent than those seen for the closely linked rs7528684 promoter variant.

The T allele is in linkage disequilibrium with rs6427389, a variant that reached genome-wide significance (OR=1.132, P=8.18×10⁻⁹) in a large IgAN GWAS meta-analysis; the authors noted that rs11264799 was the likely functional mediator through its FCRL3 eQTL activity.

The Evidence

The clearest evidence for rs11264799 comes from IgA nephropathy, a condition in which autoantibodies against galactose-deficient IgA1 drive mesangial immune complex deposition and progressive kidney disease. A large Chinese case-control study of 1,750 IgAN patients and 2,500 controls³³ large Chinese case-control study of 1,750 IgAN patients and 2,500 controls
Zhong Z, Feng S, Shi D et al. Association of FCRL3 Gene Polymorphisms with IgA Nephropathy in a Chinese Han Population. DNA Cell Biol 39:154–162, 2020 found rs11264799 significantly associated with IgAN susceptibility after Bonferroni correction, with the T allele linked to altered FCRL3 expression. A subsequent genome-wide meta-analysis across Chinese and European IgAN cohorts⁴⁴ genome-wide meta-analysis across Chinese and European IgAN cohorts
Li M et al. Genome-Wide Meta-Analysis Identifies Three Novel Susceptibility Loci. J Am Soc Nephrol 31:2045–2057, 2020 confirmed the 1q23.1 FCRL3 locus at genome-wide significance, identifying rs11264799 as the key eQTL variant underlying the association signal.

In the broader autoimmune context, a meta-analysis of 34 case-control studies⁵⁵ meta-analysis of 34 case-control studies
Yang Y, Su X, Zhang K, Zhou R. Autoimmunity 46:547–558, 2013 found rs11264799 significantly associated with autoimmune diseases in mixed ethnic subgroups, though associations in individual European or Asian populations were not consistently replicated across diseases. Heterogeneity between studies — different LD structures, disease definitions, and population ancestries — explains why single-study results for this variant are frequently negative even when the eQTL signal at the locus is robust.

For rheumatoid arthritis, multiple sclerosis, and SLE individually, rs11264799 has not shown independent replication in European cohorts; the bulk of disease association evidence for FCRL3 in these conditions is carried by the closely linked rs7528684. The evidence base for rs11264799 specifically is therefore classified as emerging.

Practical Actions

The T allele at rs11264799 acts primarily through altered FCRL3 expression, placing this variant in the same functional context as rs7528684: conditions where B cell hyperactivity and impaired immune tolerance are central. The most directly supported disease link is IgA nephropathy; broader autoimmune connections remain plausible given the eQTL mechanism but are not independently confirmed for this variant.

For TT carriers, the most actionable step is awareness of early IgAN symptoms — particularly recurrent visible haematuria (blood in urine) following upper respiratory infections, which is the hallmark presentation — and periodic urinalysis to detect subclinical proteinuria or microhaematuria before kidney function is affected.

Interactions

rs11264799 is 59 bp from rs7528684 in the FCRL3 upstream region; both variants influence FCRL3 expression and are likely to be in partial linkage disequilibrium. The rs7528684 G allele has the stronger and better-replicated autoimmune association (RA, Graves' disease, Hashimoto's thyroiditis via NF-κB binding), while rs11264799 contributes an additional eQTL layer that may operate semi-independently. Carriers of risk alleles at both loci may have amplified FCRL3 dysregulation compared to carriers of either alone, though direct compound heterozygosity data are not yet published.