What you carry at this position in your DNA and what research says about it.
Tissue Fibrosis Risk: 5/10 evidence, 40 publications.
You're viewing every possible genotype for this variant.
None of these is your result. Use the genotype toggle to compare them, then sign up and upload your DNA to see which one is yours.
Sample genotype (not yours): C/C
Higher Risk of Tissue Fibrosis and Severe Crohn's
Two copies of the C allele lead to high production of the TGF-beta1 cytokine. This increases the likelihood of excessive tissue scarring and complications in inflammatory conditions.
What this genotype means: Higher risk of intestinal strictures in Crohn's disease; Increased susceptibility to kidney scarring and IgA nephropathy; Elevated risk of lung inflammation following radiotherapy.
Sample genotype (not yours): C/G
Typical Fibrosis Risk with Altered Drug Response
Carrying one C and one G allele results in intermediate production of TGF-beta1. This genotype is associated with typical baseline risks but may alter responses to certain autoimmune medications.
What this genotype means: Typical baseline risk for tissue fibrosis and Crohn's complications; Potentially improved clinical response to rituximab; Potentially reduced clinical response to etanercept.
Sample genotype (not yours): G/G
Lower Risk of Tissue Fibrosis and Severe Crohn's
Two copies of the G allele lead to lower production of the TGF-beta1 cytokine. This provides natural protection against excessive tissue scarring and inflammatory complications.
What this genotype means: Lower risk of intestinal strictures and surgical resection in Crohn's; Reduced susceptibility to kidney fibrosis and chronic dysfunction; Lower risk of lung inflammation after radiation therapy.
Gene function and biological role
Gene Function: The TGFB1 gene encodes transforming growth factor beta 1, a multifunctional cytokine that regulates cell growth, immune function, and tissue repair [1]. It plays a critical role in controlling the inflammatory response and maintaining the structure of the extracellular matrix [2]. Overproduction of this cytokine is a primary driver of pathological tissue scarring, also known as fibrosis, across various organs [3]. Conversely, adequate levels are necessary to prevent runaway inflammation and support healthy wound healing [4].
Variant Impact: The rs1800471 variant is a missense mutation in the signal peptide of the TGFB1 gene, resulting in an arginine-to-proline substitution at codon 25 [2]. This amino acid change directly alters the secretion efficiency and circulating levels of the TGF-beta1 protein [5]. The reference C allele (encoding arginine) is associated with high cytokine production, whereas the variant G allele (encoding proline) leads to lower secretion levels [6]. Consequently, this genetic variation influences individual susceptibility to inflammatory and fibrotic complications [3].
Key Insight: The high-producing C/C genotype acts as a profibrotic factor, significantly increasing the risk of severe scarring complications in Crohn's disease and kidneys, while the G/G genotype offers protection against excessive tissue scarring.
Location: TGFB1. Chromosome 19 · 19q13.2 · 41.4 Mb
Estimated prevalence by population
Global 87.8%; European 85.1%; African 87.5%; East Asian 99.7%; South Asian 85.4%; Americas 92.0%; Ashkenazi 91.5%; Finnish 93.9%; Middle Eastern 88.8%; Amish 94.0%.
Estimated CC genotype frequency.
Global 11.7%; European 14.3%; African 12.1%; East Asian 0.3%; South Asian 14.1%; Americas 7.8%; Ashkenazi 8.3%; Finnish 6.0%; Middle Eastern 10.9%; Amish 6.0%.
Estimated CG genotype frequency.
Global 0.4%; European 0.6%; African 0.4%; East Asian < 0.1%; South Asian 0.6%; Americas 0.2%; Ashkenazi 0.2%; Finnish 0.1%; Middle Eastern 0.3%; Amish 0.1%.
Estimated GG genotype frequency.
Showing effects for C/C genotype
Immunity & Inflammation
Chronic Inflammatory Diseases
Crohn's Disease Severity. Evidence: 3/10. Source: PMID 19258388. Increased Risk.
Organ Systems
Kidney Function & Disease
Kidney Fibrosis. Evidence: 4/10. Source: PMID 19258388. Increased Risk.
Pharmacogenomics
Immunosuppressant & Biologic Response
Arthritis Drug Response. Evidence: 5/10. Source: PMID 22129793. Typical.
Cancer & Oncology
Cancer Prognosis & Treatment Outcome
Radiation Pneumonitis. Evidence: 4/10. Source: PMID 19380441. Increased Risk.
Showing effects for C/G genotype
Crohn's Disease Severity. Evidence: 3/10. Source: PMID 19258388. Typical.
Kidney Fibrosis. Evidence: 4/10. Source: PMID 19258388. Typical.
Arthritis Drug Response. Evidence: 5/10. Source: PMID 22129793. Altered Response.
Radiation Pneumonitis. Evidence: 4/10. Source: PMID 19380441. Typical.
Showing effects for G/G genotype
Crohn's Disease Severity. Evidence: 3/10. Source: PMID 19258388. Lower Risk.
Kidney Fibrosis. Evidence: 4/10. Source: PMID 19258388. Lower Risk.
Radiation Pneumonitis. Evidence: 4/10. Source: PMID 19380441. Lower Risk.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Inheriting two copies of the C allele results in the high-producing arginine form of the TGF-beta1 cytokine [1]. Elevated levels of this protein promote the deposition of collagen, driving tissue fibrosis in multiple organs [2]. In patients with Crohn's disease, this genotype is associated with a higher risk of developing strictures (narrowing of the intestines) and a shorter time to surgical resection [1]. It also increases susceptibility to IgA nephropathy and other progressive kidney diseases characterized by scarring [1]. Additionally, high-producing genotypes are linked to a greater risk of radiation pneumonitis, a form of lung inflammation that can occur after radiotherapy for lung cancer [3].
Higher risk of intestinal strictures in Crohn's disease; Increased susceptibility to kidney scarring and IgA nephropathy; Elevated risk of lung inflammation following radiotherapy.
Sample genotype: CG (Heterozygous)
Having one copy of each allele leads to intermediate levels of TGF-beta1 secretion, balancing the risks of tissue scarring and inflammation [1]. While baseline risks for Crohn's complications and kidney fibrosis remain typical, this genotype is notable for its pharmacogenomic interactions [2]. Clinical studies suggest that individuals with the C/G genotype may experience a better response to the rheumatoid arthritis drug rituximab [3]. Conversely, the same genotype has been associated with a poorer response to etanercept, another common biologic therapy [4]. These findings highlight how intermediate cytokine levels can subtly shift the efficacy of targeted immune therapies [3].
Typical baseline risk for tissue fibrosis and Crohn's complications; Potentially improved clinical response to rituximab; Potentially reduced clinical response to etanercept.
Sample genotype: GG (Homozygous)
Carrying two copies of the G allele results in the low-producing proline form of the TGF-beta1 cytokine [1]. Because lower levels of this cytokine limit the signals that trigger tissue scarring, this genotype offers a protective effect against progressive fibrosis [2]. Individuals with this genotype have a lower risk of developing strictures and requiring early surgery if they have Crohn's disease [1]. This protective profile extends to the kidneys, where lower cytokine levels reduce the risk of chronic allograft dysfunction and IgA nephropathy [2]. Furthermore, patients undergoing radiotherapy for lung cancer are at a lower risk of developing severe radiation-induced lung inflammation [3].
Lower risk of intestinal strictures and surgical resection in Crohn's; Reduced susceptibility to kidney fibrosis and chronic dysfunction; Lower risk of lung inflammation after radiation therapy.
Variants with shared genetic architecture
rs1800470 · TGFB1 Gene · Chr 19 · Cardiovascular Health
rs1800469 · TGFB1 Gene · Chr 19 · Heart Disease Risk
rs4803455 · TGFB1 Gene · Chr 19 · Heart Disease Risk
The correlation of TGFβ1 gene polymorphisms with congenital heart disease susceptibility.
Genetic markers for the efficacy of tumour necrosis factor blocking therapy in rheumatoid arthritis.
Content updated August 2026.
ReadYourDNA provides educational interpretation of DNA data you already have. It is not diagnostic, not a substitute for professional medical advice, diagnosis, or treatment, and is not intended to diagnose, treat, cure, or prevent any disease. Talk to a clinician before acting on any result.
Raw DNA Data Reports for 23andMe & AncestryDNA · About ReadYourDNA · FAQ · Methodology & Science · Pricing · Support and complaints · Legal & Contact · Health Traits · Pharmacogenomics · Carrier Status · Variant Explorer · The Human Karyotype · Privacy Policy · Terms of Service · Accessibility · Consumer Health Data Privacy · Your Privacy Choices · Editorial Standards · Your Data, Checkable · Sample Report · ReadYourDNA and Promethease compared · What is inside a 23andMe raw data file · What is inside an AncestryDNA raw data file · What a chatbot can and cannot do with your raw DNA file · Where a raw DNA file can still be uploaded in 2026
Written, maintained and operated by Martin Pechhacker, sole proprietor, Vienna, Austria. Trade register GISA 40064420. support@readyourdna.com