What you carry at this position in your DNA and what research says about it.
Alzheimer's Disease Risk: 8/10 evidence, 42 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): T/T
Lower Risk of Alzheimer's Disease
Presence of two protective T alleles is linked to a lower risk of late-onset Alzheimer's disease. This genetic profile supports higher expression of the PICALM gene, which aids in brain plaque clearance.
What this genotype means: ~15% lower risk of late-onset Alzheimer's disease; Increased PICALM gene expression in brain microvessels; Slightly higher brain iron levels.
Sample genotype (not yours): C/C
Typical Risk of Alzheimer's Disease
Presence of two common C alleles is associated with a typical baseline risk of late-onset Alzheimer's disease. This genetic profile represents the standard baseline for PICALM gene expression.
What this genotype means: Typical baseline risk of late-onset Alzheimer's disease; Standard PICALM gene expression levels; Typical brain iron levels.
Sample genotype (not yours): T/C
Presence of one protective T allele is linked to a lower risk of late-onset Alzheimer's disease. This genetic profile supports healthy PICALM gene expression and brain plaque clearance.
Gene function and biological role
Gene Function: The PICALM gene encodes the phosphatidylinositol-binding clathrin assembly protein, which is highly expressed in brain microvessels and neurons [1]. This protein plays a critical role in clathrin-mediated endocytosis, a process cells use to internalize molecules [1]. Specifically, PICALM regulates the trafficking of amyloid precursor protein and the clearance of amyloid-beta across the blood-brain barrier [2]. It also helps guide the recycling of synaptic vesicles in neurons, supporting healthy brain cell communication [2].
Variant Impact: The rs3851179 variant is located in an intergenic region upstream of the PICALM gene and modulates its expression levels [1]. The protective T allele is associated with increased expression of PICALM in brain microvessels [1]. Higher levels of PICALM are thought to facilitate more efficient clearance of amyloid-beta plaques from the brain [2]. Conversely, the C allele is linked to lower PICALM expression, which may reduce the brain's capacity to clear these toxic proteins [2].
Key Insight: The protective T allele of this variant is linked to increased expression of the PICALM gene, which helps clear toxic amyloid-beta plaques from the brain.
Location: PICALM. Chromosome 11 · 11q14.2 · 86.2 Mb
Estimated prevalence by population
Global 10.5%; European 13.3%; African 2.4%; East Asian 15.8%; South Asian 15.0%; Americas 13.2%; Ashkenazi 15.5%; Finnish 12.4%; Middle Eastern 14.8%; Amish 23.0%.
Estimated TT genotype frequency.
Global 40.9%; European 46.3%; African 26.2%; East Asian 47.9%; South Asian 47.5%; Americas 46.3%; Ashkenazi 47.8%; Finnish 45.6%; Middle Eastern 47.3%; Amish 49.9%.
Estimated TC genotype frequency.
Global 48.6%; European 40.4%; African 71.4%; East Asian 36.2%; South Asian 37.5%; Americas 40.6%; Ashkenazi 36.7%; Finnish 42.0%; Middle Eastern 37.9%; Amish 27.1%.
Estimated CC genotype frequency.
Showing effects for T/T genotype
Neurology & Mental Health
Neurodegenerative Diseases
Alzheimer's Disease. Evidence: 8/10. Source: PMID 19734902. ~15% Lower Risk.
Nutrition & Metabolism
Blood Chemistry & Metabolites
Brain Iron Levels. Evidence: 5/10. Source: PMID 38789058. Slightly Higher.
Cardiovascular & Metabolic
Blood Cell & Iron Traits
Platelet Width. Evidence: 6/10. Source: PMID 32888494. Slightly Higher.
Showing effects for C/C genotype
Alzheimer's Disease. Evidence: 8/10. Source: PMID 19734902. Typical Risk.
Brain Iron Levels. Evidence: 5/10. Source: PMID 38789058. Typical.
Platelet Width. Evidence: 6/10. Source: PMID 32888494. Typical.
Showing effects for T/C genotype
What this genotype means for the people who carry it
Sample genotype: TT (Homozygous)
Two copies of the protective T allele are associated with a roughly 15% reduction in the risk of developing late-onset Alzheimer's disease [1]. This protective effect is driven by increased expression of the PICALM gene, particularly in the brain's microvasculature [2]. Higher PICALM levels facilitate the efficient transport and clearance of amyloid-beta proteins across the blood-brain barrier, preventing plaque accumulation [2]. Research also suggests that carriers of this protective variant maintain better functional brain connectivity and cognitive reserve as they age [3]. Additionally, this genotype is associated with slightly higher brain iron levels in certain regions, though the clinical significance of this remains under study [4].
~15% lower risk of late-onset Alzheimer's disease; Increased PICALM gene expression in brain microvessels; Slightly higher brain iron levels.
Sample genotype: CC (Homozygous)
Two copies of the common C allele represent the standard genetic baseline for late-onset Alzheimer's disease risk [1]. This genotype is associated with typical, baseline expression levels of the PICALM gene in the brain [2]. Because it lacks the protective T allele, it does not benefit from the enhanced amyloid-beta clearance associated with higher PICALM expression [2]. However, it is important to note that this genotype is highly common, carried by the majority of the population, and does not represent an elevated risk beyond the standard population baseline [1]. Additionally, this genotype is associated with typical brain iron levels and standard platelet distribution width.
Typical baseline risk of late-onset Alzheimer's disease; Standard PICALM gene expression levels; Typical brain iron levels.
Sample genotype: TC (Heterozygous)
One copy of the protective T allele is associated with a roughly 15% reduction in the risk of late-onset Alzheimer's disease [1]. This protective effect is driven by increased expression of the PICALM gene, particularly in the brain's microvasculature [2]. Higher PICALM levels facilitate the efficient transport and clearance of amyloid-beta proteins across the blood-brain barrier, preventing plaque accumulation [2]. Research also suggests that carriers of this protective variant maintain better functional brain connectivity and cognitive reserve as they age [3]. Additionally, this genotype is associated with slightly higher brain iron levels in certain regions, though the clinical significance of this remains under study [4].
Variants with shared genetic architecture
rs10792832 · PICALM Gene · Chr 11 · Alzheimer Disease Risk
rs11218343 · SORL1 Gene · Chr 11 · Alzheimer's Risk
rs9331896 · CLU Gene · Chr 8 · Alzheimer's Disease Risk
Genetics of PICALM expression and Alzheimer's disease.
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