What you carry at this position in your DNA and what research says about it.
Cholesterol Levels: 9/10 evidence, 26 publications.
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Sample genotype (not yours): G/G
Higher Cholesterol and Colorectal Cancer Risk
Elevated levels of LDL and total cholesterol characterize this genetic profile. There is also a slightly increased risk of developing colorectal cancer.
What this genotype means: Higher LDL and total cholesterol levels; Increased risk of colorectal cancer; Slightly lower risk of Crohn's disease.
Sample genotype (not yours): G/T
Sample genotype (not yours): T/T
Lower Cholesterol and Colorectal Cancer Risk
Reduced levels of LDL and total cholesterol characterize this genetic profile. There is also a lower risk of developing colorectal cancer.
What this genotype means: Lower LDL and total cholesterol levels; Reduced risk of colorectal cancer; Slightly higher risk of Crohn's disease.
Gene function and biological role
Gene Function: The MYRF gene encodes myelin regulatory factor, a transcription factor vital for central nervous system myelination. However, this specific genetic region is highly complex and sits in a tightly linked haplotype block with the FADS1 gene cluster [1]. The FADS1 gene encodes delta-5 desaturase, a key enzyme that regulates the biosynthesis of polyunsaturated fatty acids [2]. Because of this close genetic proximity, variants in this region strongly influence how the body processes dietary fats [2]. This metabolic control directly impacts circulating lipid levels and inflammatory pathways throughout the body [1].
Variant Impact: Located within an intron of the MYRF gene, this genetic change serves as a powerful proxy for genetic variation in the neighboring FADS1 gene [1]. The change alters DNA methylation in an enhancer region that controls the expression of fatty acid desaturases [1]. Specifically, the G allele is associated with significantly higher activity of the delta-5 desaturase enzyme [3]. This increased enzymatic activity accelerates the conversion of precursor fats into arachidonic acid and other long-chain polyunsaturated fatty acids [3]. Consequently, this single nucleotide change acts as a major genetic determinant of blood lipid profiles and inflammatory mediator levels [4].
Key Insight: This single genetic variant accounts for nearly 19% of the variation in blood levels of arachidonic acid, an essential omega-6 fatty acid.
Location: MYRF. Chromosome 11 · 11q12.2 · 61.8 Mb
Origin Story: This genetic region shows strong evidence of positive selection in human history, likely driven by dietary adaptations to local environments and the availability of plant- versus animal-based fatty acids.
Estimated prevalence by population
Global 52.7%; European 44.2%; African 84.2%; East Asian 20.0%; South Asian 64.6%; Americas 26.3%; Ashkenazi 51.3%; Finnish 33.5%; Middle Eastern 42.2%; Amish 59.0%.
Estimated GG genotype frequency.
Global 36.9%; European 44.6%; African 15.1%; East Asian 49.4%; South Asian 31.5%; Americas 50.0%; Ashkenazi 40.6%; Finnish 48.7%; Middle Eastern 45.5%; Amish 35.6%.
Estimated GT genotype frequency.
Global 10.4%; European 11.2%; African 0.7%; East Asian 30.6%; South Asian 3.8%; Americas 23.8%; Ashkenazi 8.0%; Finnish 17.7%; Middle Eastern 12.3%; Amish 5.4%.
Estimated TT genotype frequency.
Showing effects for G/G genotype
Cancer & Oncology
Colorectal Cancer
Colorectal Cancer. Evidence: 8/10. Source: PMID 36539618. ~1.14x Risk.
Cardiovascular & Metabolic
Lipids & Cholesterol
LDL Cholesterol. Evidence: 9/10. Source: PMID 30275531. Higher LDL.
HDL Cholesterol. Evidence: 8/10. Source: PMID 30275531. Slightly Higher.
Immunity & Inflammation
Chronic Inflammatory Diseases
Crohn's Disease. Evidence: 5/10. Source: PMID 26192919. Typical Risk.
Nutrition & Metabolism
Macronutrient Metabolism
Arachidonic Acid Levels. Evidence: 4/10. Source: PMID 24962583. Higher Levels.
Showing effects for G/T genotype
Colorectal Cancer. Evidence: 8/10. Source: PMID 36539618. Increased Risk.
Arachidonic Acid Levels. Evidence: 4/10. Source: PMID 24962583. Moderate Levels.
Showing effects for T/T genotype
Colorectal Cancer. Evidence: 8/10. Source: PMID 36539618. Typical Risk.
LDL Cholesterol. Evidence: 9/10. Source: PMID 30275531. Lower LDL.
HDL Cholesterol. Evidence: 8/10. Source: PMID 30275531. Slightly Lower.
Crohn's Disease. Evidence: 5/10. Source: PMID 26192919. ~1.09x Risk.
Arachidonic Acid Levels. Evidence: 4/10. Source: PMID 24962583. Lower Levels.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Highly efficient delta-5 desaturase enzyme activity is characteristic of this genetic profile [1]. This efficiency leads to elevated levels of arachidonic acid, an omega-6 fatty acid that serves as a precursor to pro-inflammatory molecules [1]. While higher desaturase activity can be beneficial under certain dietary conditions, it is consistently associated with higher circulating low-density lipoprotein (LDL) and total cholesterol levels [2]. Large-scale genetic studies have also identified a clear link between this profile and an increased risk of colorectal cancer [3]. Conversely, this genetic setup appears to offer a slight protective effect against Crohn's disease [4]. Managing dietary fat intake, particularly balancing omega-3 and omega-6 fatty acids, is often highlighted as a key lifestyle factor for individuals with this profile [1]. Incorporating more marine-derived omega-3 fatty acids may help balance the inflammatory pathways [1]. Clinical guidelines often emphasize the importance of monitoring lipid profiles for individuals with elevated cholesterol markers [2]. Understanding how genetic factors influence lipid metabolism can help tailor personalized nutritional approaches [1].
Higher LDL and total cholesterol levels; Increased risk of colorectal cancer; Slightly lower risk of Crohn's disease.
Sample genotype: GT (Heterozygous)
Elevated delta-5 desaturase enzyme activity is commonly observed with this genetic profile [1]. This enzymatic efficiency increases the production of arachidonic acid, which can promote inflammatory pathways in the body [1]. Population studies show that individuals with this profile tend to have higher low-density lipoprotein (LDL) and total cholesterol levels compared to those with the T/T genotype [2]. Furthermore, genome-wide association studies link this profile to an elevated risk of colorectal cancer [3]. On the other hand, the G allele is associated with a slightly reduced risk of developing Crohn's disease [4]. Dietary strategies that focus on reducing pro-inflammatory fats and increasing anti-inflammatory omega-3s are highly relevant for this genetic profile [1]. Balancing these fatty acids helps mitigate the downstream inflammatory effects of high desaturase activity [1]. Standard health guidelines suggest that tracking lipid levels can be beneficial for managing overall cardiovascular risk [2]. Personalized dietary adjustments remain a primary focus for optimizing metabolic health [1].
Sample genotype: TT (Homozygous)
Significantly reduced delta-5 desaturase enzyme activity is the hallmark of this genetic profile [1]. This reduced activity leads to much lower levels of arachidonic acid, an omega-6 fatty acid involved in inflammatory processes [1]. As a result, individuals with this genotype typically enjoy lower low-density lipoprotein (LDL) and total cholesterol levels [2]. Large-scale genetic analyses also show that this profile is associated with a lower risk of colorectal cancer [3]. However, this reduced desaturase activity can make it harder for the body to synthesize long-chain polyunsaturated fatty acids from plant sources, making dietary intake of pre-formed omega-3s (like EPA and DHA) more important [1]. Additionally, this genotype is associated with a slightly increased risk of Crohn's disease [4]. Ensuring adequate intake of marine-based fats can help support optimal fatty acid balance [1]. Healthcare providers often look at the full lipid panel to assess cardiovascular health comprehensively [2]. Maintaining a balanced diet rich in diverse nutrient sources supports overall metabolic function [1].
Lower LDL and total cholesterol levels; Reduced risk of colorectal cancer; Slightly higher risk of Crohn's disease.
Variants with shared genetic architecture
rs174533 · MYRF Gene · Chr 11 · Colorectal Cancer Risk
rs174535 · MYRF Gene · Chr 11 · Fatty Acid Metabolism
rs509360 · MYRF Gene · Chr 11 · Omega-3 Metabolism
Uncovering the DNA methylation landscape in key regulatory regions within the FADS cluster.
Content updated August 2026.
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