rs11652075 — CARD14 CARD14 Arg820Trp (R820W)

CARD14 Arg820Trp — The Psoriasis Biologic Response Predictor

CARD14 is a scaffold protein¹¹ scaffold protein
A non-enzymatic protein that organizes signaling complexes at cellular membranes expressed primarily in keratinocytes — the epidermal cells that form the skin barrier. Under inflammatory conditions, CARD14 recruits BCL10 and MALT1 to form an activation complex that triggers NF-κB²² NF-κB
Nuclear Factor kappa-light-chain-enhancer of activated B cells; a master regulator of inflammation that switches on dozens of proinflammatory genes signaling, producing TNF-α, IL-17, IL-23, and other cytokines that drive skin inflammation. The rs11652075 variant changes arginine to tryptophan at position 820 (p.Arg820Trp), altering the protein's regulatory domain in a way that affects how readily this NF-κB amplification cascade activates. This SNP carries two clinically distinct pieces of information: it slightly raises the odds of developing psoriasis, and it strongly predicts whether anti-TNF biologic therapy will achieve remission.

The Mechanism

Position 820 of CARD14 sits in the coiled-coil domain³³ coiled-coil domain
A structural motif formed by two or more alpha-helices wound around each other; in CARD14, this domain controls protein-protein interaction with BCL10 and governs complex formation efficiency that controls interaction with BCL10. The arginine-to-tryptophan substitution replaces a positively charged, hydrophilic residue with a bulky aromatic one. Functional assays by Jordan et al. demonstrated that CARD14 variants affecting this region produced NF-κB activation levels >2.5-fold above wild-type⁴⁴ >2.5-fold above wild-type
Measured by luciferase reporter assay in HEK293 cells transfected with CARD14 expression constructs; two variants required TNF-α stimulation to show full activation in cell-based assays. The variant also destroys a CpG dinucleotide methylation site⁵⁵ destroys a CpG dinucleotide methylation site
CpG sites are targets for DNA methylation; when the C>T substitution occurs at a CpG, the cytosine can no longer be methylated, potentially altering epigenetic silencing of the region, which may affect transcriptional regulation of nearby sequences. The biological net effect is a keratinocyte NF-κB pathway that operates at a mildly lower activation threshold, releasing more TNF-α and IL-17A under the same inflammatory stimuli — explaining both the modest psoriasis susceptibility and the robust response to TNF blockade.

The Evidence

The Jordan et al. 2012 study in American Journal of Human Genetics established the foundational evidence: across seven psoriasis cohorts with more than 6,000 cases and 4,000 controls⁶⁶ more than 6,000 cases and 4,000 controls
Cohorts included European, North American, and Australasian ancestry groups, rs11652075 reached genome-wide significance for psoriasis association (p=2.1×10⁻⁶). Notably, adjustment for the major HLA-Cw*0602 psoriasis risk allele strengthened the CARD14 signal, confirming it operates through an independent pathway.

A subsequent meta-analysis by Shi et al. pooled five studies totaling 32,807 cases and 45,458 controls⁷⁷ five studies totaling 32,807 cases and 45,458 controls
Ancestry breakdown: European and East Asian populations both represented and confirmed the T allele is protective against psoriasis (pooled OR=0.877, 95%CI 0.834–0.922, P<0.001), with consistent effects in both European (OR=0.883) and Asian (OR=0.872) populations. The effect is modest per allele — the primary clinical utility of this variant lies in pharmacogenomics, not risk stratification.

The pharmacogenomic evidence is more striking. Coto-Segura et al. sequenced the entire CARD14 gene in 116 psoriasis patients treated with TNF inhibitors⁸⁸ 116 psoriasis patients treated with TNF inhibitors
79 responders, 37 non-responders; response defined as PASI 75 reduction at week 24; anti-TNF agents included adalimumab, etanercept, and infliximab. The CC genotype (no T allele) was significantly enriched among responders (OR=3.71, 95%CI 1.30–10.51, P=0.01). Patients with CC genotype were nearly four times more likely to achieve PASI 75 response by week 24. The mechanistic interpretation is straightforward: if CARD14-mediated NF-κB activity is the dominant driver of a patient's psoriasis, TNF-α blockade more effectively disrupts that pathway; patients with the protective T allele may have psoriasis driven by other mechanisms less responsive to anti-TNF therapy.

Practical Actions

For people without psoriasis, the CC genotype conveys only modest susceptibility — well under 1% absolute lifetime risk increase from this variant alone. For those who do develop psoriasis and are considering biologic therapy, CC status is meaningful: it identifies them as likely responders to adalimumab, etanercept, or infliximab before a single injection is given. For CT and TT carriers who develop psoriasis, anti-TNF therapy remains an option but response is less reliably predicted by this variant; IL-17 or IL-23 inhibitors may be comparably or more effective choices depending on other clinical factors.

The T allele's destruction of a CpG methylation site does not currently have specific management implications — no dietary or supplement intervention has been shown to compensate for epigenetic dysregulation at this locus.

Interactions

CARD14 rs11652075 operates in the PSORS2 psoriasis susceptibility locus and interacts with the major PSORS1 locus (HLA-Cw*0602). The Jordan 2012 data showed that conditioning on HLA-Cw*0602 status actually increased the CARD14 signal, suggesting the two loci contribute to psoriasis through partly non-overlapping mechanisms. For pharmacogenomics purposes, rs61751629 (another CARD14 coding variant) has been examined alongside rs11652075; the combination of CARD14 rare variants also predicted favorable anti-TNF response in the Coto-Segura dataset. These interactions are candidates for compound action assessment pending larger pharmacogenomic study replication.