rs104895467 — NOD2 NOD2 N852S

NOD2 N852S — A Rare Bacterial-Sensing Variant Enriched in Ashkenazi Jewish Populations

Deep inside your intestinal lining, immune sentinel cells continuously survey the bacterial population that colonizes your gut. NOD2 (nucleotide-binding oligomerization domain-containing protein 2)¹¹ NOD2 (nucleotide-binding oligomerization domain-containing protein 2)
an intracellular pattern-recognition receptor expressed in intestinal epithelial cells, Paneth cells, and monocytes; detects muramyl dipeptide (MDP), a fragment of bacterial cell-wall peptidoglycan, to trigger NF-κB-mediated antimicrobial defense is the sentinel's core machinery. NOD2 was identified in 2001 as the first Crohn's disease susceptibility gene²² identified in 2001 as the first Crohn's disease susceptibility gene
discovered through positional cloning of the IBD1 locus on chromosome 16q12 by Hugot et al. and independently by Ogura et al., and it remains the single strongest genetic risk factor for this condition.

rs104895467 encodes the N852S substitution — asparagine replaced by serine at position 852 in the protein's leucine-rich repeat (LRR) domain³³ leucine-rich repeat (LRR) domain
the C-terminal sensing region of NOD2 that makes direct contact with muramyl dipeptide; mutations in this domain are the mechanistic basis for all three major Crohn's disease NOD2 variants. This is a rare variant globally (G allele frequency ~0.07%), but it shows a striking enrichment in Ashkenazi Jewish populations⁴⁴ enrichment in Ashkenazi Jewish populations
~1.56% G allele frequency in Ashkenazi Jewish individuals per gnomAD v4 exomes (26,134 samples), approximately 40-fold higher than in non-Jewish European populations; this pattern of Ashkenazi enrichment is shared by several other rare NOD2 variants and is consistent with founder effects in that population.

The Mechanism

The N852S substitution sits within the NOD2 leucine-rich repeat domain, the same region disrupted by all three major Crohn's disease NOD2 mutations (R702W, G908R, L1007fs). The LRR domain directly senses bacterial muramyl dipeptide (MDP), a peptidoglycan fragment shed by virtually all bacteria. When NOD2 binds MDP, it activates NF-κB⁵⁵ activates NF-κB
the canonical inflammatory transcription factor; NOD2-mediated NF-κB activation drives expression of antimicrobial peptides (defensins), cytokines, and chemokines that coordinate the mucosal immune response and triggers antimicrobial defenses. LRR domain missense variants impair this MDP-sensing step.

Functional studies of Crohn's-associated NOD2 variants demonstrate that LRR-domain missense changes share a common signaling defect — reduced NF-κB activation in response to bacterial ligands⁶⁶ LRR-domain missense changes share a common signaling defect — reduced NF-κB activation in response to bacterial ligands
despite retaining MDP-binding capacity, the variants fail to efficiently transduce the downstream signal; Hsp70 chaperone interaction can partially restore function, suggesting the variants cause conformational instability rather than complete loss of ligand recognition. The net consequence is reduced output of alpha-defensins (HD-5 and HD-6)⁷⁷ alpha-defensins (HD-5 and HD-6)
antimicrobial peptides secreted by Paneth cells in the ileal crypts; defensin deficiency allows bacterial dysbiosis in the terminal ileum from the ileal Paneth cells that express NOD2 at the highest levels in the body.

When NOD2 fails to properly clear and contain gut bacteria, a second consequence emerges: impaired cross-regulation of Toll-like receptor signaling⁸⁸ Toll-like receptor signaling
NOD2 normally dampens TLR2/4 activation by gut commensals; when NOD2 is weakened, the TLR-driven inflammatory axis runs less regulated, predisposing the mucosa to dysregulated cytokine release. The result is a mucosal environment that oscillates between inadequate microbial clearance and excessive inflammatory signaling — the dual defect underlying Crohn's disease pathogenesis.

The Evidence

The three major NOD2 Crohn's disease variants have been extensively characterized. In a meta-analysis of 75 case-control studies⁹⁹ meta-analysis of 75 case-control studies
18,727 CD cases and 17,102 controls; Yazdanyar et al. 2009, the per-allele odds ratios were: R702W (OR 2.2), G908R (OR 2.6), and L1007fs (OR 3.8), with compound heterozygotes carrying OR 9.0 for Crohn's disease. These are among the largest effect sizes documented for any common complex disease.

rs104895467 (N852S) is a rare variant not individually characterized in most large association studies, but is annotated in ClinVar with an "Association" relationship to regional enteritis (Crohn's disease). Structurally, it falls in the same LRR sensing domain as the three established risk variants, and deep resequencing studies¹⁰¹⁰ deep resequencing studies
Rivas et al. 2011; pooled resequencing of 56 IBD-associated genes across 16,054 CD cases, 12,153 UC cases, and 17,575 controls have established that the NOD2 LRR domain harbors multiple rare variants with independent disease associations beyond the three classical mutations.

The striking enrichment of this variant in Ashkenazi Jewish populations (~40-fold above non-Jewish European frequency) is clinically relevant: Ashkenazi Jewish individuals have elevated rates of Crohn's disease, and NOD2 variants appear to contribute disproportionately to this risk. The N852S frequency in this population (1.56%) means carrier status is not uncommon among Ashkenazi Jewish individuals reporting gastrointestinal symptoms.

NOD2 variants as a class predict a specific disease phenotype: a meta-analysis of 49 studies¹¹¹¹ meta-analysis of 49 studies
8,893 subjects with 2,897 NOD2 mutation carriers; Adler et al. 2011 found that NOD2 mutations increase the risk of complicated (stricturing or fistulizing) Crohn's disease by 33% compared to NOD2 wild-type patients. NOD2 variant carriers are specifically at risk for ileal disease — the segment where NOD2 is most highly expressed and Paneth cell antimicrobial function is most dependent on NOD2 signaling.

Practical Implications

Carrying one copy of the G allele (AG genotype) means one of your two NOD2 copies has a leucine-rich repeat domain change that may impair MDP sensing and NF-κB activation. Your other NOD2 copy remains functional. The primary clinical implication is vigilance for Crohn's disease symptoms — especially those pointing to the terminal ileum — and early evaluation when symptoms arise.

Since impaired NOD2 signaling affects ileal Paneth cell function and microbiome composition¹²¹² ileal Paneth cell function and microbiome composition
NOD2-deficient intestinal epithelium shows increased colonization by Enterobacteriaceae and reduced Firmicutes diversity, particularly in the ileum, strategies that support gut microbial diversity are specifically relevant for NOD2 variant carriers.

Interactions

N852S belongs to the class of LRR-domain NOD2 variants that, when present alongside a second NOD2 risk allele on the opposite chromosome (compound heterozygosity), produce a markedly elevated risk profile — the OR of ~9.0 for compound heterozygotes documented in the Yazdanyar 2009 meta-analysis applies to biallelic NOD2 states generally. If rs104895467 is carried alongside rs2066844 (R702W, OR 2.2), rs2066845 (G908R, OR 2.6), or rs2066847 (L1007fs, OR 3.8) on the other chromosome, the combined risk profile requires clinical attention.

NOD2 also interacts with ATG16L1 rs2241880¹³¹³ ATG16L1 rs2241880
the T300A autophagy variant that cooperates with NOD2 in bacterial clearance via selective autophagy (xenophagy); carriers of both NOD2 and ATG16L1 risk alleles show additive impairment of intestinal bactericidal function. The downstream NF-κB pathway shared by NOD2 and TNFAIP3¹⁴¹⁴ TNFAIP3
the A20 deubiquitinase that terminates NOD2-triggered NF-κB signaling; A20 loss-of-function variants can amplify the baseline inflammatory state in NOD2 risk carriers represents another axis where variants compound.