What you carry at this position in your DNA and what research says about it.
Fatty Acid Metabolism: 10/10 evidence, 29 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
Efficient Omega Fatty Acid Conversion and Lower Triglycerides
Highly active desaturase enzymes enable efficient conversion of plant-based fats into essential long-chain fatty acids. This metabolic profile is associated with lower blood triglyceride levels but slightly higher total and LDL cholesterol.
What this genotype means: Highly efficient conversion of plant-based omega fats; Lower baseline triglyceride levels; Slightly higher LDL and total cholesterol.
Sample genotype (not yours): C/T
Typical Omega Fatty Acid Conversion and Lipid Levels
A balanced combination of active and less active desaturase alleles results in moderate conversion of plant-based fats. Blood levels of triglycerides, LDL, and HDL cholesterol are generally close to population averages.
What this genotype means: Moderate conversion of plant-derived fatty acids; Typical baseline triglyceride and cholesterol levels; Responsive to dietary fatty acid adjustments.
Sample genotype (not yours): T/T
Reduced Omega Fatty Acid Conversion and Higher Triglycerides
Lower desaturase enzyme activity limits the body's ability to synthesize essential long-chain fatty acids from plant sources. This metabolic profile is linked to higher triglyceride levels but lower LDL and total cholesterol.
What this genotype means: Reduced conversion of plant-derived omega fats; Higher baseline triglyceride levels; Lower baseline LDL and total cholesterol.
Gene function and biological role
Gene Function: FADS1 encodes fatty acid desaturase 1, a key enzyme in the biosynthesis of highly important long-chain polyunsaturated fatty acids [1]. It catalyzes the rate-limiting delta-5 desaturase step, converting precursors into arachidonic acid and eicosapentaenoic acid [2]. These fatty acids serve as critical structural components of cell membranes and precursors for inflammatory signaling molecules [3]. Genetic variation in this gene cluster significantly influences blood lipid profiles and metabolic health across diverse populations [4].
Variant Impact: Located in the 3 prime untranslated region of the FADS1 gene, rs174546 is a single nucleotide polymorphism that alters the binding of regulatory microRNAs [5]. The C allele represents the highly active version of the enzyme, promoting rapid conversion of plant-derived fatty acids into long-chain polyunsaturated fatty acids [2]. Conversely, the T allele introduces a microRNA binding site that downregulates gene expression, leading to reduced desaturase activity [1]. This molecular shift directly impacts circulating levels of cholesterol, triglycerides, and essential fatty acids [6].
Key Insight: Carriers of the T/T genotype have a reduced ability to convert plant-based omega-3 and omega-6 fats into active long-chain forms, making direct dietary sources like fish more important.
Location: FADS1. Chromosome 11 · 11q12.2 · 61.8 Mb
Estimated prevalence by population
Global 52.9%; European 44.1%; African 85.0%; East Asian 19.9%; South Asian 67.4%; Americas 26.3%; Ashkenazi 50.9%; Finnish 33.5%; Middle Eastern 42.7%; Amish 58.8%.
Estimated CC genotype frequency.
Global 36.7%; European 44.6%; African 14.3%; East Asian 49.4%; South Asian 29.4%; Americas 50.0%; Ashkenazi 40.9%; Finnish 48.7%; Middle Eastern 45.3%; Amish 35.7%.
Estimated CT genotype frequency.
Global 10.4%; European 11.3%; African 0.6%; East Asian 30.7%; South Asian 3.2%; Americas 23.8%; Ashkenazi 8.2%; Finnish 17.7%; Middle Eastern 12.0%; Amish 5.4%.
Estimated TT genotype frequency.
Showing effects for C/C genotype
Nutrition & Metabolism
Macronutrient Metabolism
Omega-3 Conversion. Evidence: 4/10. Source: PMID 20691134. Highly Efficient.
Cardiovascular & Metabolic
Lipids & Cholesterol
Triglycerides. Evidence: 10/10. Source: PMID 20686565. Lower Levels.
LDL Cholesterol. Evidence: 10/10. Source: PMID 29507422. Slightly Higher.
HDL Cholesterol. Evidence: 9/10. Source: PMID 20686565. Slightly Higher.
Total Cholesterol. Evidence: 10/10. Source: PMID 20686565. Slightly Higher.
Blood Cell & Iron Traits
Iron Binding Capacity. Evidence: 7/10. Source: PMID 33536631. Typical.
Showing effects for C/T genotype
Omega-3 Conversion. Evidence: 4/10. Source: PMID 20691134. Moderate.
Triglycerides. Evidence: 10/10. Source: PMID 20686565. Typical Levels.
LDL Cholesterol. Evidence: 10/10. Source: PMID 29507422. Typical Levels.
HDL Cholesterol. Evidence: 9/10. Source: PMID 20686565. Typical Levels.
Total Cholesterol. Evidence: 10/10. Source: PMID 20686565. Typical Levels.
Iron Binding Capacity. Evidence: 7/10. Source: PMID 33536631. Slightly Higher.
Showing effects for T/T genotype
Omega-3 Conversion. Evidence: 4/10. Source: PMID 20691134. Reduced.
Triglycerides. Evidence: 10/10. Source: PMID 20686565. Higher Levels.
LDL Cholesterol. Evidence: 10/10. Source: PMID 29507422. Slightly Lower.
HDL Cholesterol. Evidence: 9/10. Source: PMID 20686565. Slightly Lower.
Total Cholesterol. Evidence: 10/10. Source: PMID 20686565. Slightly Lower.
Iron Binding Capacity. Evidence: 7/10. Source: PMID 33536631. Higher.
What this genotype means for the people who carry it
Sample genotype: CC (Homozygous)
Active delta-5 desaturase enzymes efficiently process dietary plant oils, such as alpha-linolenic acid and linoleic acid, into long-chain polyunsaturated fatty acids like arachidonic acid and EPA [1]. This rapid conversion supports cellular membrane integrity and healthy lipid signaling [2]. Large-scale genomic studies consistently link this highly active metabolic state to lower circulating triglycerides [3]. However, the same efficient pathway is associated with slightly elevated levels of LDL and total cholesterol [4]. These minor cholesterol elevations are typically offset by higher levels of protective HDL cholesterol [5]. Dietary strategies focusing on balanced omega-3 and omega-6 intake can help optimize this metabolic profile [6].
Highly efficient conversion of plant-based omega fats; Lower baseline triglyceride levels; Slightly higher LDL and total cholesterol.
Sample genotype: CT (Heterozygous)
Moderate delta-5 desaturase activity provides a balanced rate of converting short-chain plant fats into long-chain polyunsaturated fatty acids [1]. Circulating levels of arachidonic acid and other essential lipids remain within the typical range [2]. Population studies show that intermediate carriers exhibit average baseline levels of triglycerides and total cholesterol [3]. This balanced genetic background offers flexibility, as lipid levels remain responsive to dietary fat quality [4]. While the conversion of plant-based omega-3s to EPA is moderate, incorporating direct sources of long-chain fatty acids like seafood can support optimal health [5]. Overall cardiovascular risk markers associated with this locus are typical [6].
Moderate conversion of plant-derived fatty acids; Typical baseline triglyceride and cholesterol levels; Responsive to dietary fatty acid adjustments.
Sample genotype: TT (Homozygous)
Reduced delta-5 desaturase activity significantly limits the conversion of plant-derived short-chain fatty acids into essential long-chain polyunsaturated fatty acids [1]. Consequently, blood levels of arachidonic acid and EPA are typically lower, while precursor fatty acids accumulate [2]. This metabolic bottleneck is strongly associated with elevated circulating triglycerides [3]. Conversely, this slower pathway leads to lower circulating levels of LDL and total cholesterol [4]. Because synthesis of long-chain omega-3s is less efficient, direct dietary intake of EPA and DHA from marine sources is highly beneficial [5]. Adjusting the dietary ratio of omega-6 to omega-3 fatty acids can help manage the associated lipid changes [6].
Reduced conversion of plant-derived omega fats; Higher baseline triglyceride levels; Lower baseline LDL and total cholesterol.
Variants with shared genetic architecture
rs174554 · FADS1 Gene · Chr 11 · Omega Fat Conversion
rs174545 · FADS1 Gene · Chr 11 · Fatty Acid Metabolism
rs174550 · FADS1 Gene · Chr 11 · Omega Fatty Acid Processing
Genetic analyses of diverse populations improves discovery for complex traits.
Biological, clinical and population relevance of 95 loci for blood lipids.
A large electronic-health-record-based genome-wide study of serum lipids.
Discovery and refinement of loci associated with lipid levels.
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