What you carry at this position in your DNA and what research says about it.
Heart Disease Risk: 8/10 evidence, 18 publications.
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Sample genotype (not yours): G/G
Higher Risk of Heart Disease and Stroke
Two copies of the G allele are associated with elevated LDL cholesterol and a higher likelihood of cardiovascular events. This common genetic profile represents the baseline risk for arterial plaque buildup.
What this genotype means: Higher baseline LDL cholesterol; Elevated risk of coronary artery disease; Increased susceptibility to ischemic stroke.
Sample genotype (not yours): G/T
Typical Cardiovascular Risk Profile
One copy of the protective T allele provides an intermediate cardiovascular profile. Cholesterol levels and heart disease risks generally align with the population average.
What this genotype means: Average baseline LDL cholesterol; Typical risk of coronary artery disease; Standard stroke susceptibility.
Sample genotype (not yours): T/T
Lower Risk of Heart Disease and Stroke
Two copies of the T allele confer significant protection against cardiovascular disease. This genotype is linked to lower LDL cholesterol levels and reduced arterial plaque formation.
What this genotype means: Lower baseline LDL cholesterol; Reduced risk of myocardial infarction; Decreased susceptibility to ischemic stroke.
Gene function and biological role
Gene Function: The SMARCA4 gene encodes a key subunit of the SWI/SNF chromatin remodeling complex, which regulates gene expression by altering chromosome structure. This complex plays a critical role in cellular development, differentiation, and DNA repair across various tissues. Genetic variations in this region can influence the expression of neighboring genes, including the low-density lipoprotein receptor gene [1]. Through these regulatory pathways, the gene is closely linked to lipid metabolism and the development of atherosclerosis [2]. Altered expression levels are also implicated in vascular inflammation and plaque stability [3].
Variant Impact: The rs1122608 variant is an intronic change located within the SMARCA4 gene on chromosome 19. This genetic marker is situated near the LDLR gene, which is highly critical for clearing low-density lipoprotein cholesterol from the bloodstream [2]. The variation is thought to act as a regulatory switch, affecting the splicing and expression of nearby transcripts [1]. Specifically, the major G allele is associated with higher circulating cholesterol levels and an elevated risk of cardiovascular events [4]. Conversely, the minor T allele is linked to reduced lipid levels and a lower incidence of arterial disease [5].
Key Insight: The protective T allele of this variant reduces the risk of ischemic stroke by regulating an mRNA splicing factor rather than directly altering the SMARCA4 protein itself.
Location: SMARCA4. Chromosome 19 · 19p13.2 · 11.1 Mb
Estimated prevalence by population
Global 68.3%; European 56.2%; African 90.0%; East Asian 80.6%; South Asian 56.8%; Americas 70.1%; Ashkenazi 57.6%; Finnish 62.2%; Middle Eastern 65.5%; Amish 60.1%.
Estimated GG genotype frequency.
Global 27.8%; European 37.5%; African 9.7%; East Asian 18.4%; South Asian 37.2%; Americas 27.3%; Ashkenazi 36.6%; Finnish 33.4%; Middle Eastern 30.8%; Amish 34.9%.
Estimated GT genotype frequency.
Global 3.9%; European 6.3%; African 0.3%; East Asian 1.0%; South Asian 6.1%; Americas 2.7%; Ashkenazi 5.8%; Finnish 4.5%; Middle Eastern 3.6%; Amish 5.1%.
Estimated TT genotype frequency.
Showing effects for G/G genotype
Cardiovascular & Metabolic
Heart Disease
Heart Disease. Evidence: 8/10. Source: PMID 21378990. Increased Risk.
Stroke
Stroke. Evidence: 6/10. Source: PMID 24262325. Increased Risk.
Lipids & Cholesterol
Cholesterol Levels. Evidence: 5/10. Source: PMID 31566214. Higher LDL.
Hypertension
Hypertension. Evidence: 3/10. Source: PMID 31507094. Increased Risk.
Showing effects for G/T genotype
Heart Disease. Evidence: 8/10. Source: PMID 21378990. Typical Risk.
Stroke. Evidence: 6/10. Source: PMID 24262325. Typical Risk.
Cholesterol Levels. Evidence: 5/10. Source: PMID 31566214. Typical LDL.
Hypertension. Evidence: 3/10. Source: PMID 31507094. Typical Risk.
Showing effects for T/T genotype
Heart Disease. Evidence: 8/10. Source: PMID 21378990. Decreased Risk.
Stroke. Evidence: 6/10. Source: PMID 24262325. Decreased Risk.
Cholesterol Levels. Evidence: 5/10. Source: PMID 31566214. Lower LDL.
Hypertension. Evidence: 3/10. Source: PMID 31507094. Decreased Risk.
What this genotype means for the people who carry it
Sample genotype: GG (Homozygous)
Inheriting two copies of the G allele correlates with higher circulating levels of total and LDL cholesterol [1]. This lipid elevation contributes directly to the gradual accumulation of arterial plaque, increasing the risk of coronary artery disease and myocardial infarction [2]. Large-scale genome-wide association studies consistently identify this genotype as a risk factor for early-onset heart attacks [3]. Furthermore, the G allele is associated with an increased susceptibility to ischemic stroke and large artery stroke [4]. Cellular studies suggest this variant may influence the expression of splicing factors that regulate vascular inflammation [5]. Maintaining a heart-healthy lifestyle is particularly important for individuals with this common genetic baseline.
Higher baseline LDL cholesterol; Elevated risk of coronary artery disease; Increased susceptibility to ischemic stroke.
Sample genotype: GT (Heterozygous)
Carrying a single copy of the T allele offers moderate protection against the lipid-elevating effects of the major G allele [1]. This intermediate status typically results in average circulating cholesterol levels and standard baseline risks for coronary artery disease [2]. Clinical studies show that the presence of one T allele helps mitigate the risk of early-onset myocardial infarction compared to the G/G genotype [3]. Splicing efficiency of vascular regulatory genes remains balanced, resulting in typical susceptibility to ischemic stroke [4]. Standard cardiovascular screening and routine lipid panels are generally sufficient to monitor health. Lifestyle factors such as diet and exercise continue to play the primary role in determining overall heart health.
Average baseline LDL cholesterol; Typical risk of coronary artery disease; Standard stroke susceptibility.
Sample genotype: TT (Homozygous)
Possessing two copies of the minor T allele is strongly associated with lower levels of total and LDL cholesterol [1]. This favorable lipid profile significantly reduces the long-term risk of developing coronary artery disease and experiencing a myocardial infarction [2]. Research indicates that the T allele helps protect against ischemic stroke by increasing the expression of SFRS3, a splicing regulator that limits vascular inflammation [3]. This molecular mechanism helps maintain healthier, more resilient arterial walls over time. The protective effect remains evident even in populations with established vascular risk factors [4]. While genetics provide a protective advantage, maintaining healthy habits remains beneficial for overall longevity.
Lower baseline LDL cholesterol; Reduced risk of myocardial infarction; Decreased susceptibility to ischemic stroke.
Variants with shared genetic architecture
rs1333049 · CDKN2B-AS1 Gene · Chr 9 · Heart Disease Risk
rs2207132 · Chr 20 · Heart Disease Risk
rs2244608 · HNF1A Gene · Chr 12 · Heart Disease Risk
Quantitative and Qualitative Role of Antagonistic Heterogeneity in Genetics of Blood Lipids.
Large-scale association analysis identifies 13 new susceptibility loci for coronary artery disease.
Content updated August 2026.
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