📅 15 July 2026 🏷️ Alzheimer's Genetics ⏱️ 8 min read 👩‍🔬 Linda Osaghale

rs429358, rs3178166, and rs111371860 Explained

In our study, three genetic variants stood out from the rest. They were genome-wide significant, replicated across independent cohorts, and had powerful effects on Alzheimer's disease risk.

But what are these variants? What do they do? And what do they mean for you?

Let's meet them.

Three Alzheimer's risk variants: rs429358 (4.58x higher risk), rs3178166 (protective), and rs111371860 (1.44x higher risk)
Figure 1: Three genetic variants in the APOE region significantly affect Alzheimer's disease risk. Based on Osaghale et al. (2026).

Variant 1: rs429358 (The APOE4 Variant)

The Star of the Show

CharacteristicDetail
Chromosome19
Position45,411,941
Effect AlleleC
Other AlleleT
Effect Allele Frequency0.1802
Beta1.5224
SE0.0508
Odds Ratio4.58
95% CI4.15 – 5.06
P-value5.20 × 10⁻¹⁹⁷

What This Means

MetricInterpretation
OR = 4.58Carriers have nearly 5 times higher risk of Alzheimer's
P = 5.20 × 10⁻¹⁹⁷This association is as real as it gets
Effect allele = CThis is the "risk" allele
EAF = 18.02%About 18% of the population carries this variant

How It Works

rs429358 is the variant that defines the APOE4 allele. It causes a change in the APOE protein that:

Who Carries It?

GenotypeRiskFrequency
No APOE4 (ε3/ε3)Baseline~60%
One APOE4 (ε3/ε4)3x higher~25%
Two APOE4 (ε4/ε4)15x higher~2-3%

Variant 2: rs3178166 (The Protective Variant)

The Unexpected Hero

CharacteristicDetail
Chromosome19
Position45,594,170
Effect AlleleG
Other AlleleA
Effect Allele Frequency0.4949
Beta-0.2229
SE0.0330
Odds Ratio0.80
95% CI0.75 – 0.85
P-value1.53 × 10⁻¹¹

What This Means

MetricInterpretation
OR = 0.80Carriers have 20% lower risk of Alzheimer's
P = 1.53 × 10⁻¹¹Highly significant association
Effect allele = GThis is the "protective" allele
EAF = 49.49%About half the population carries this variant

How It Works

rs3178166 is located near the APOC1 gene, which is involved in lipid metabolism. The protective effect may work through:

Why This Matters

If half the population carries a protective variant, this has huge public health implications. Even small protective effects at the individual level can have large population-level impacts.

Variant 3: rs111371860 (The Risk Variant)

The Hidden Danger

CharacteristicDetail
Chromosome19
Position45,345,787
Effect AlleleT
Other AlleleA
Effect Allele Frequency0.0976
Beta0.3660
SE0.0585
Odds Ratio1.44
95% CI1.29 – 1.62
P-value3.91 × 10⁻¹⁰

What This Means

MetricInterpretation
OR = 1.44Carriers have 44% higher risk of Alzheimer's
P = 3.91 × 10⁻¹⁰Very strong association
Effect allele = TThis is the "risk" allele
EAF = 9.76%About 10% of the population carries this variant

How It Works

rs111371860 is located near the PVRL2 gene, which is involved in cell adhesion. The risk effect may work through:

Why This Matters

Although the effect is smaller than rs429358, 1.44x risk is still significant. With 10% of the population carrying this variant, many people are affected.

The Big Picture: All Three Variants

Chromosome 19 Locus

All three variants are located on chromosome 19, within a region of strong linkage disequilibrium (LD).

Chromosome 19: 45,345,787 - 45,602,781
[----------------------------------------]
    ↑                  ↑                ↑
rs111371860      rs429358        rs3178166
(44% ↑ risk)    (4.58x ↑ risk)  (20% ↓ risk)

This means these variants are inherited together. People who carry the risk alleles often carry multiple risk variants.

Combined Effects

ScenarioRisk
No risk allelesBaseline
rs111371860 only1.44x higher
rs429358 only4.58x higher
rs429358 + rs111371860~6.6x higher
rs429358 + rs3178166 (protective)~3.7x higher
All three (2 risk, 1 protective)~5.3x higher

The protective variant rs3178166 can partially offset the risk from APOE4.

What This Means for You

Genetic Testing

ScenarioRecommendation
APOE4 carrierConsider early screening, lifestyle interventions
APOE4 + rs111371860Higher risk, consider clinical trial participation
rs3178166 carrierSome protection, continue standard recommendations
No risk variantsAverage risk, standard recommendations

Clinical Implications

The Bottom Line

Together, these variants paint a complex picture of Alzheimer's risk. And they're all on chromosome 19.

Key Takeaways

VariantEffectRisk
rs429358Risk-increasing4.58x higher
rs3178166Protective20% lower
rs111371860Risk-increasing44% higher

What do you think?

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Osaghale L, Beshiru A, Subhan U. (2026). Replication-guided functional genomic prioritization of regulatory risk variants in Alzheimer's disease. Gene Reports. 44: 102551.

DOI: https://doi.org/10.1016/j.genrep.2026.102551


Next post: "The mTOR Connection: How Cellular Metabolism Could Hold the Key to Alzheimer's" — Coming soon!

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