What you carry at this position in your DNA and what research says about it.
Fatty Liver Protection: 9/10 evidence, 35 publications.
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Sample genotype (not yours): A/A
Strong Protection Against Fatty Liver
Two copies of the protective threonine allele significantly lower the risk of developing fatty liver and cirrhosis. This genotype is associated with lower liver fat, reduced liver enzymes, and healthier cholesterol profiles.
What this genotype means: Significantly lower risk of fatty liver disease; Lower circulating liver enzymes; Lower total and LDL cholesterol.
Sample genotype (not yours): A/G
Reduced Risk of Fatty Liver
Carrying one copy of the protective threonine allele provides moderate protection against fatty liver disease and liver scarring. It is linked to lower liver fat accumulation and reduced liver enzyme levels.
What this genotype means: Moderately lower risk of fatty liver disease; Reduced risk of liver cirrhosis; Slightly lower cholesterol levels.
Sample genotype (not yours): G/G
Typical Risk of Fatty Liver
Two copies of the common alanine allele are associated with typical levels of MTARC1 enzyme activity and standard liver disease risk. This genotype does not benefit from the protective, fat-lowering effects of the threonine variant.
What this genotype means: Standard baseline risk of fatty liver disease; Typical liver enzyme levels; Standard baseline cholesterol levels.
Gene function and biological role
Gene Function: The MTARC1 gene encodes mitochondrial amidoxime reducing component 1, an enzyme anchored to the outer membrane of mitochondria [1]. It plays a key role in lipid metabolism, mitochondrial redox reactions, and the processing of certain compounds in the liver [1] [2]. Research indicates that reducing the activity or stability of this enzyme helps protect hepatocytes from accumulating excess fat [2] [3]. By limiting lipid accumulation, MTARC1 inhibition reduces cellular stress and prevents downstream inflammatory pathways [3]. Consequently, this gene has emerged as a major therapeutic target for metabolic liver disorders [3].
Variant Impact: The rs2642438 variant is a missense mutation in the MTARC1 gene that substitutes the amino acid alanine with threonine at position 165 [4]. This specific structural change destabilizes the MTARC1 protein, leading to its rapid degradation and reduced cellular levels [4] [3]. Because it acts as a natural loss-of-function change, it mimics the effects of therapeutic gene inhibition [3]. This reduction in active enzyme levels prevents excess fat accumulation and cellular damage in liver tissue [3] [1]. As a result, the variant is highly studied for its profound protective effects against progressive liver diseases [1].
Key Insight: A natural genetic defect that destabilizes this liver enzyme actually acts as a powerful shield, protecting the liver from fat accumulation and scarring.
Location: MTARC1. Chromosome 1 · 1q41 · 220.8 Mb
Estimated prevalence by population
Global 5.8%; European 8.6%; African 0.7%; East Asian 4.7%; South Asian 4.9%; Americas 4.9%; Ashkenazi 10.5%; Finnish 8.7%; Middle Eastern 7.6%; Amish 3.3%.
Estimated AA genotype frequency.
Global 33.0%; European 41.4%; African 15.2%; East Asian 33.9%; South Asian 34.6%; Americas 34.4%; Ashkenazi 43.8%; Finnish 41.6%; Middle Eastern 39.9%; Amish 29.8%.
Estimated AG genotype frequency.
Global 61.2%; European 50.0%; African 84.1%; East Asian 61.4%; South Asian 60.5%; Americas 60.7%; Ashkenazi 45.7%; Finnish 49.6%; Middle Eastern 52.5%; Amish 66.9%.
Estimated GG genotype frequency.
Showing effects for A/A genotype
Organ Systems
Liver Function & Disease
Fatty Liver Disease. Evidence: 9/10. Source: PMID 32298765. Lowest Risk.
Liver Cirrhosis. Evidence: 10/10. Source: PMID 33310085. Lowest Risk.
Liver Enzyme Levels. Evidence: 10/10. Source: PMID 33547301. Lowest Levels.
Cardiovascular & Metabolic
Lipids & Cholesterol
Cholesterol Levels. Evidence: 10/10. Source: PMID 29507422. Lowest Levels.
Triglycerides. Evidence: 10/10. Source: PMID 30698716. Slightly Higher.
Showing effects for A/G genotype
Fatty Liver Disease. Evidence: 9/10. Source: PMID 32298765. Reduced Risk.
Liver Cirrhosis. Evidence: 10/10. Source: PMID 33310085. Reduced Risk.
Liver Enzyme Levels. Evidence: 10/10. Source: PMID 33547301. Lower Levels.
Cholesterol Levels. Evidence: 10/10. Source: PMID 29507422. Lower Levels.
Showing effects for G/G genotype
Fatty Liver Disease. Evidence: 9/10. Source: PMID 32298765. Typical Risk.
Liver Cirrhosis. Evidence: 10/10. Source: PMID 33310085. Typical Risk.
Liver Enzyme Levels. Evidence: 10/10. Source: PMID 33547301. Typical Levels.
Cholesterol Levels. Evidence: 10/10. Source: PMID 29507422. Typical Levels.
Triglycerides. Evidence: 10/10. Source: PMID 30698716. Typical Levels.
What this genotype means for the people who carry it
Sample genotype: AA (Homozygous)
Inheriting two copies of the protective threonine allele leads to a significant reduction in MTARC1 protein stability and function [1]. This natural reduction in enzyme activity prevents the buildup of lipids within hepatocytes, keeping liver fat levels low [2]. Clinical studies show that this genotype is strongly associated with a lower risk of non-alcoholic fatty liver disease and its progression to cirrhosis [2] [3]. It also correlates with lower circulating levels of alanine aminotransferase, a key marker of liver cell injury [4]. Additionally, total and LDL cholesterol levels tend to be lower in these individuals [5]. Although triglyceride levels may be slightly higher, the overall metabolic profile remains highly protective against liver damage [6].
Significantly lower risk of fatty liver disease; Lower circulating liver enzymes; Lower total and LDL cholesterol.
Sample genotype: AG (Heterozygous)
Possessing one copy of the protective threonine allele and one copy of the typical alanine allele results in intermediate MTARC1 enzyme activity [1]. This partial reduction in active protein levels is sufficient to help limit lipid accumulation in liver cells [2]. Large-scale genetic studies demonstrate that carriers have a reduced risk of developing non-alcoholic fatty liver disease and liver cirrhosis compared to non-carriers [2] [3]. This protective effect is also reflected in lower blood levels of liver enzymes like alanine aminotransferase, indicating less ongoing liver stress [4]. Furthermore, carriers typically exhibit lower total and LDL cholesterol levels [5]. While triglyceride levels might show a very slight increase, the overall impact is highly beneficial for long-term liver health [6].
Moderately lower risk of fatty liver disease; Reduced risk of liver cirrhosis; Slightly lower cholesterol levels.
Sample genotype: GG (Homozygous)
Carrying two copies of the common alanine allele results in fully stable and active MTARC1 enzymes within liver cells [1]. Without the destabilizing threonine variant, liver cells maintain standard rates of lipid processing and are more susceptible to fat accumulation under metabolic stress [2]. This genotype represents the baseline risk for non-alcoholic fatty liver disease and progressive liver scarring in the general population [2] [3]. Blood levels of liver enzymes such as alanine aminotransferase tend to be higher compared to carriers of the protective variant, reflecting typical liver cell turnover [4]. Total and LDL cholesterol levels also remain at standard baseline levels [5]. Maintaining a balanced diet and active lifestyle is particularly important for individuals with this typical genotype to support optimal liver health [6].
Standard baseline risk of fatty liver disease; Typical liver enzyme levels; Standard baseline cholesterol levels.
Variants with shared genetic architecture
rs2642442 · MTARC1 Gene · Chr 1 · Fatty Liver Disease Risk
rs17321515 · TRIB1 Gene · Chr 8 · Blood Lipid Levels
rs2954021 · TRIB1 Gene · Chr 8 · Heart and Liver Health
A large electronic-health-record-based genome-wide study of serum lipids.
Multiancestry Genome-Wide Association Study of Lipid Levels Incorporating Gene-Alcohol Interactions.
Content updated August 2026.
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