What you carry at this position in your DNA and what research says about it.
Crohn's Disease Risk: 9/10 evidence, 37 publications.
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Sample genotype (not yours): G/G
Typical Crohn's Disease Risk
Two copies of the typical gene version are present, which encodes a fully functional bacterial sensor.
What this genotype means: Typical risk of Crohn's disease; Normal bacterial sensing in the gut.
Sample genotype (not yours): G/GC
~3x Higher Crohn's Disease Risk
One copy of the insertion variant is present, which is linked to a moderately increased risk of developing Crohn's disease.
What this genotype means: ~3x higher risk of Crohn's disease; Increased risk of inflammatory bowel disease; Higher risk of pouchitis after surgery.
Sample genotype (not yours): GC/GC
~35x Higher Crohn's Disease Risk
Two copies of the insertion variant are present, which is associated with a highly elevated risk of developing Crohn's disease.
What this genotype means: ~35x higher risk of Crohn's disease; Highly aggressive Crohn's disease course if diagnosed; Highly increased risk of inflammatory bowel disease.
Gene function and biological role
Gene Function: The NOD2 gene encodes a protein that acts as an intracellular sensor for bacterial components [1]. It plays a vital role in the immune system by recognizing peptidoglycans from bacterial cell walls and triggering an inflammatory response to clear pathogens [2]. This process is essential for maintaining a healthy balance of microbes in the gut [3]. When NOD2 is mutated or dysfunctional, the body's ability to sense and respond to gut bacteria is compromised, leading to chronic, uncontrolled inflammation [4].
Variant Impact: A single-base insertion of cytosine in exon 11 of the NOD2 gene defines this variant [5]. This insertion shifts the reading frame during protein synthesis, resulting in a truncated, non-functional NOD2 protein [1]. The shortened protein lacks the critical leucine-rich repeat domain needed to detect bacterial cell wall components [2]. Consequently, immune cells cannot properly recognize gut microbes, leading to impaired bacterial clearance and chronic intestinal inflammation [4].
Key Insight: This variant is a frameshift mutation that truncates the NOD2 protein, completely disabling its ability to sense gut bacteria.
Location: NOD2. Chromosome 16 · 16q12.1 · 50.7 Mb
Estimated prevalence by population
Global 97.1%; European 95.4%; African 99.3%; East Asian > 99.9%; South Asian 100.0%; Americas 97.4%; Ashkenazi 94.4%; Finnish 96.4%; Middle Eastern 99.3%; Amish 94.0%.
Estimated GG genotype frequency.
Global 2.9%; European 4.5%; African 0.7%; East Asian < 0.1%; South Asian 0.0%; Americas 2.6%; Ashkenazi 5.5%; Finnish 3.6%; Middle Eastern 0.7%; Amish 6.0%.
Estimated GGC genotype frequency.
Global < 0.1%; European 0.1%; African < 0.1%; East Asian < 0.1%; South Asian 0.0%; Americas < 0.1%; Ashkenazi 0.1%; Finnish < 0.1%; Middle Eastern < 0.1%; Amish 0.1%.
Estimated GCGC genotype frequency.
Showing effects for G/G genotype
Immunity & Inflammation
Chronic Inflammatory Diseases
Crohn's Disease. Evidence: 9/10. Source: PMID 11385577. Typical Risk.
Inflammatory Bowel Disease. Evidence: 9/10. Source: PMID 23128233. Typical Risk.
Pouchitis. Evidence: 3/10. Source: PMID 20940596. Typical Risk.
Organ Systems
Liver Function & Disease
Spontaneous Peritonitis. Evidence: 3/10. Source: PMID 21745302. Typical Risk.
Showing effects for G/GC genotype
Crohn's Disease. Evidence: 9/10. Source: PMID 11385577. ~3x Increased Risk.
Inflammatory Bowel Disease. Evidence: 9/10. Source: PMID 23128233. Increased Risk.
Pouchitis. Evidence: 3/10. Source: PMID 20940596. Increased Risk.
Spontaneous Peritonitis. Evidence: 3/10. Source: PMID 21745302. Increased Risk.
Showing effects for GC/GC genotype
Crohn's Disease. Evidence: 9/10. Source: PMID 11385577. ~35x Increased Risk.
Inflammatory Bowel Disease. Evidence: 9/10. Source: PMID 23128233. Highly Increased Risk.
Pouchitis. Evidence: 3/10. Source: PMID 20940596. Highly Increased Risk.
Spontaneous Peritonitis. Evidence: 3/10. Source: PMID 21745302. Highly Increased Risk.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Normal, fully functional versions of the NOD2 gene are present in this genotype. Your immune cells can properly detect bacterial cell wall components in the gut and trigger appropriate inflammatory responses to clear them [1]. Because your bacterial sensing system is intact, you do not have the highly elevated risk of chronic intestinal inflammation associated with the insertion variant [2]. Large-scale genome-wide association studies confirm that this genotype is associated with typical, baseline susceptibility to Crohn's disease and general inflammatory bowel disease [3]. It is also associated with a typical risk for secondary complications like spontaneous bacterial peritonitis in individuals with liver cirrhosis [4]. Maintaining a healthy gut microbiome through diet and lifestyle remains beneficial for overall digestive health. Standard preventative care and a balanced diet are generally sufficient to support your digestive tract. No special genetic monitoring or clinical interventions are typically recommended for this baseline profile.
Typical risk of Crohn's disease; Normal bacterial sensing in the gut.
Sample genotype: GGC (Heterozygous)
One copy of the frameshift insertion allele is present in this genotype, meaning that a portion of your NOD2 proteins are truncated and unable to detect bacterial cell wall components [1]. This impairment moderately compromises your gut's immune defense, leading to a higher likelihood of chronic intestinal inflammation [2]. Clinical studies show that heterozygous carriers have an approximately 2- to 4-fold increased risk of developing Crohn's disease compared to the general population [3]. This genotype is also associated with a higher risk of general inflammatory bowel disease and related complications [4]. In patients who undergo certain bowel surgeries, carrying this variant increases the risk of developing pouchitis, an inflammation of the surgically created pouch [5]. Additionally, in individuals with liver cirrhosis, this variant is linked to an increased risk of spontaneous bacterial peritonitis [6]. Knowing this risk can help you and your healthcare provider monitor for early digestive symptoms. Maintaining a healthy gut microbiome through diet and lifestyle may also be beneficial.
~3x higher risk of Crohn's disease; Increased risk of inflammatory bowel disease; Higher risk of pouchitis after surgery.
Sample genotype: GCGC (Homozygous)
Two copies of the frameshift insertion allele are present in this genotype, meaning that you produce virtually no functional NOD2 proteins, leaving your immune system severely compromised in its ability to detect gut bacteria [1]. This complete loss of function triggers a highly dysregulated, aggressive inflammatory response in the digestive tract [2]. Research indicates that individuals with this genotype have an approximately 20- to 40-fold (often cited as ~35-fold) higher risk of developing Crohn's disease [3]. If Crohn's disease develops, homozygous carriers are highly prone to an aggressive disease course, characterized by ileal involvement, strictures, fistulas, and a high rate of surgery [4]. This genotype is also strongly linked to general inflammatory bowel disease and severe complications [5]. Furthermore, it significantly increases the risk of chronic pouchitis after surgery in ulcerative colitis patients [6] and spontaneous bacterial peritonitis in those with liver cirrhosis [7]. Early awareness of this genetic predisposition is highly valuable for proactive digestive health management. Discussing these findings with a specialist can help guide personalized wellness and monitoring strategies.
~35x higher risk of Crohn's disease; Highly aggressive Crohn's disease course if diagnosed; Highly increased risk of inflammatory bowel disease.
Variants with shared genetic architecture
rs2066845 · NOD2 Gene · Chr 16 · Crohn's Disease Risk
rs2076756 · NOD2 Gene · Chr 16 · Crohn's Disease Risk
rs2066844 · NOD2 Gene · Chr 16 · Crohn's Disease Risk
Association of NOD2 leucine-rich repeat variants with susceptibility to Crohn's disease.
Patients with inflammatory bowel disease exhibit dysregulated responses to microbial DNA.
Host-microbe interactions have shaped the genetic architecture of inflammatory bowel disease.
A frameshift mutation in NOD2 associated with susceptibility to Crohn's disease.
Genome-wide association defines more than 30 distinct susceptibility loci for Crohn's disease.
NOD2/CARD15 mutations correlate with severe pouchitis after ileal pouch-anal anastomosis.
Content updated August 2026.
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