What you carry at this position in your DNA and what research says about it.
Psoriasis and Cancer Risk: 4/10 evidence, 50 publications.
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Sample genotype (not yours): T/T
Higher Psoriasis Risk and Typical Cancer Risk
Susceptibility to psoriasis and psoriatic arthritis is elevated with this genetic profile. Conversely, baseline risks for cervical cancer and multiple sclerosis remain typical.
What this genotype means: ~1.4x higher risk of psoriasis; Increased susceptibility to Crohn's disease; Typical baseline risk for cervical cancer.
Sample genotype (not yours): G/G
Higher Risk of Cervical Cancer and Multiple Sclerosis
Elevated risks for cervical cancer and multiple sclerosis are associated with this genetic profile. On the other hand, it offers strong protection against psoriasis.
What this genotype means: Increased risk of cervical cancer; Higher susceptibility to multiple sclerosis; Lower risk of psoriasis.
Sample genotype (not yours): T/G
Typical Psoriasis Risk but Higher Cervical Cancer Risk
Protection against psoriasis is a key feature of this genetic profile. However, a moderately increased risk of developing cervical cancer is also present.
What this genotype means: Increased risk of cervical cancer; Typical baseline risk for psoriasis; Typical baseline risk for multiple sclerosis.
Gene function and biological role
Gene Function: The IL12B gene encodes the p40 subunit, a crucial protein component shared by two major pro-inflammatory cytokines, interleukin-12 and interleukin-23 [1]. These cytokines play a pivotal role in directing the immune system's T-cell responses, particularly the Th1 and Th17 pathways that drive inflammatory processes [2]. Proper regulation of IL12B is essential for defending against pathogens, but overproduction can lead to chronic inflammation and autoimmune diseases [3]. Conversely, insufficient activity of these cytokines can impair the body's ability to clear viral infections and eliminate abnormal cells [4].
Variant Impact: The rs3212227 variant is located in the 3 prime untranslated region of the IL12B gene, a region that influences gene expression and mRNA stability [5]. This genetic change alters the production levels of the IL-12p40 subunit, thereby shifting the balance of inflammatory signaling in the body [6]. Depending on which allele is present, this shift can either heighten susceptibility to autoimmune conditions or alter the defense against certain cancers [4]. It is one of the most widely studied immune-system variants, showing strong associations with diverse inflammatory disorders [3].
Key Insight: A single genetic change in the IL12B gene acts as a biological trade-off, where alleles that protect against skin inflammation simultaneously increase the risk of certain viral-related cancers.
Location: IL12B. Chromosome 5 · 5q33.3 · 159.3 Mb
Estimated prevalence by population
Global 54.8%; European 63.9%; African 43.9%; East Asian 28.7%; South Asian 40.5%; Americas 44.4%; Ashkenazi 69.4%; Finnish 67.4%; Middle Eastern 51.0%; Amish 64.7%.
Estimated TT genotype frequency.
Global 37.6%; European 32.0%; African 44.7%; East Asian 49.7%; South Asian 46.3%; Americas 44.5%; Ashkenazi 27.8%; Finnish 29.4%; Middle Eastern 40.8%; Amish 31.5%.
Estimated TG genotype frequency.
Global 7.6%; European 4.0%; African 11.4%; East Asian 21.6%; South Asian 13.2%; Americas 11.1%; Ashkenazi 2.8%; Finnish 3.2%; Middle Eastern 8.2%; Amish 3.8%.
Estimated GG genotype frequency.
Showing effects for T/T genotype
Organ Systems
Skin & Hair Conditions
Psoriasis. Evidence: 4/10. Source: PMID 23297015. ~1.4x Increased Risk.
Cancer & Oncology
Gynecological Cancers
Cervical Cancer. Evidence: 3/10. Source: PMID 22614250. Typical Risk.
Immunity & Inflammation
Autoimmune Diseases
Multiple Sclerosis. Evidence: 3/10. Source: PMID 30069682. Typical Risk.
Chronic Inflammatory Diseases
Crohn's Disease. Evidence: 3/10. Source: PMID 33390082. Increased Risk.
Showing effects for G/G genotype
Psoriasis. Evidence: 4/10. Source: PMID 23297015. Typical Risk.
Cervical Cancer. Evidence: 3/10. Source: PMID 22614250. ~1.3x Increased Risk.
Multiple Sclerosis. Evidence: 3/10. Source: PMID 30069682. Increased Risk.
Crohn's Disease. Evidence: 3/10. Source: PMID 33390082. Typical Risk.
Showing effects for T/G genotype
What this genotype means for the people who carry it
Sample genotype: TT (Homozygous)
Presence of two copies of the T allele leads to higher expression of the IL12B gene, which increases the production of inflammatory cytokines [1]. This heightened immune response can trigger chronic skin inflammation, resulting in a 1.43-fold increased risk of developing psoriasis and psoriatic arthritis [2]. Additionally, this inflammatory state is linked to a higher susceptibility to colonic Crohn's disease [3]. On the positive side, the T/T genotype does not carry the elevated risk of cervical cancer or multiple sclerosis associated with the G allele [4]. Maintaining a balanced lifestyle with anti-inflammatory habits can help manage the autoimmune risks associated with this profile.
~1.4x higher risk of psoriasis; Increased susceptibility to Crohn's disease; Typical baseline risk for cervical cancer.
Sample genotype: GG (Homozygous)
Possessing two copies of the G allele is associated with lower baseline levels of certain inflammatory cytokines, which helps protect against psoriasis [1]. However, this reduced immune surveillance can make it harder for the body to eliminate persistent viral infections like HPV, leading to a significantly increased risk of cervical cancer [2]. Furthermore, the G/G genotype has been linked to a higher susceptibility and faster progression of multiple sclerosis [3]. Research indicates that this genetic change alters the delicate balance of Th1 and Th17 immune cells, affecting both viral defense and neuroinflammation [4]. Prioritizing routine health screenings and supporting overall immune health are key strategies for managing these risks.
Increased risk of cervical cancer; Higher susceptibility to multiple sclerosis; Lower risk of psoriasis.
Sample genotype: TG (Heterozygous)
A single copy of the G allele alters the regulation of the IL-12p40 subunit, resulting in a more balanced response against skin inflammation [1]. Consequently, this genotype does not carry the elevated risk of psoriasis and psoriatic arthritis seen in T/T homozygotes [2]. However, the presence of the G allele is associated with a roughly 1.3-fold increased risk of cervical cancer [3]. This is thought to occur because the genetic variation slightly reduces the immune system's efficiency in clearing human papillomavirus (HPV) infections [4].
Increased risk of cervical cancer; Typical baseline risk for psoriasis; Typical baseline risk for multiple sclerosis.
Variants with shared genetic architecture
rs12188300 · IL12B Gene · Chr 5 · Psoriasis Risk
rs2546890 · IL12B Gene · Chr 5 · Autoimmune Disease Risk
rs3213094 · IL12B Gene · Chr 5 · Psoriasis and Biologic Response
Meta-analysis of IL12B polymorphisms (rs3212227, rs6887695) with psoriasis and psoriatic arthritis.
Contribution of IL12A and IL12B polymorphisms to the risk of cervical cancer.
Content updated August 2026.
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