rs9472817
A SNP in the SLC25A27 gene on chromosome 6. Its most notable genotype is C;C: CC genotype increases risk of Alzheimer's in epsilon 4s.
- Gene
- SLC25A27
- Location
- Chr 646,673,255 (GRCh38)
- Highest magnitude
- 2.1Worth knowing
- Tested on
- 23andMe
Genotypes
As shown in 23andMe and AncestryDNA files.
- C;CMost notableBadCC genotype increases risk of Alzheimer's in epsilon 4s.
- C;GBadCG genotype increases Alzheimer's risk relative to GG in epsilon 4s
- G;GGoodReduces risk of Alzheimer's in those with epsilon 4
On SNPedia: (C;C), (C;G), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Frequency
Share of each genotype in 4 HapMap populations.
- AverageC;C 33% C;G 44% G;G 23%
- European ancestry (Utah)C;C 31% C;G 48% G;G 22%
- Han Chinese (Beijing)C;C 11% C;G 60% G;G 29%
- Japanese (Tokyo)C;C 36% C;G 38% G;G 27%
- Yoruba (Nigeria)C;C 55% C;G 29% G;G 16%
Notes
From SNPedia
Show notes, about 200 words
Homozygote carriers of the C allele who were also carriers of epsilon 4 genotype were at increased risk of LOAD (Late onset Alzheimer's disease). However, homozygote carriers of the G allele who were also carriers of epsilon 4 genotype had their increased risk of Alzheimer's reduced .
C;C
The article on the SNP page noted that those with CC and APOE epsilon 4 had increased risk of Alzheimer's as compared with those only with epsilon 4. This result will need to be confirmed in a larger study. Also it is not clear what the implications are for those with homozygous epsilon 4 genotype.
C;G
The risk of AD among those carrying an epsilon 4 and heterozygote gentotype at rs9472817 was intermediate between the other two homozygous genotypes. In the study cited for this SNP no specific p value is given for this heterozygote zygote result, though the CG genotype when considered in conjunction with epsilon 4 carriage yielded a p-value of p=1.02 * 10-13.
G;G
The initial report noted on the SNP page found that those with GG and epsilon 4 genotype had their increased risk of Alzheimer's annulled. It not clear whether this applies only to single epsilon 4 carriers. Also, further research will be necessary to confirm this in larger samples.
Source and license
Adapted from rs9472817 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.
SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.