rs3849942

A SNP in the LOC107987057 gene on chromosome 9. Its most notable genotype is T;T: 1.4x increased risk for ALS

Gene
LOC107987057
Location
Chr 927,543,283 (GRCh38)
Highest magnitude
1.4Minor
Tested on
23andMe, AncestryDNA
Minor allele frequency
19%

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. T;TMost notableBad1.4x increased risk for ALSMinor · 1.44% of people
  2. C;TBad1.2x increased risk for ALSMinor · 1.227% of people
  3. C;CGoodnormalTypical · 0.069% of people

SNPedia records rs3849942 on the minus strand: (A;A), (A;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 11 HapMap populations.

  • AverageT;T 4% C;T 27% C;C 69%
  • European ancestry (Utah)T;T 9% C;T 29% C;C 62%
  • Han Chinese (Beijing)T;T <1% C;T 13% C;C 86%
  • Japanese (Tokyo)T;T 0% C;T 15% C;C 85%
  • Yoruba (Nigeria)T;T 3% C;T 38% C;C 59%
  • African ancestry (Southwest US)T;T 5% C;T 28% C;C 67%
  • Chinese (Denver)T;T <1% C;T 17% C;C 83%
  • Gujarati IndianT;T 1% C;T 25% C;C 74%
  • Luhya (Kenya)T;T 7% C;T 41% C;C 52%
  • Mexican ancestry (Los Angeles)T;T 2% C;T 5% C;C 93%
  • Maasai (Kenya)T;T 10% C;T 40% C;C 50%
  • TuscanT;T 10% C;T 41% C;C 49%

Other LOC107987057 SNPs

All LOC107987057 SNPs

Notes

From SNPedia

Show notes, about 140 words

rs3849942 is one of 2 SNPs from the ch 9p21.2 region associated in a large GWAS study with ALS risk, the other SNP being rs2814707. In this study, the reported odds ratio for rs3849942(A) was 1.22 (CI: 1.15 - 1.30, p = 4.64 x 10e-10). The odds ratio for the minor rs3849942(A) allele was 1.15 (p=1.01x10e-8). From a study of 405 Finnish patients with ALS, rs3849942 was found within a 42 SNP haplotype associated with highly increased (p = 7 x 10e-33) risk when patients with familial ALS were compared to controls (odds ratio of 21.0, CI: 11.2-39.1). This haplotype overlapped with a region reported (by others) to associate with risk for frontotemporal dementia. In terms of population attributable risk, for the 93 patients with familial ALS, this 9p21 locus accounts for 38% and that of rs13048019 (on ch 21q22) for 25%.

Source and license

Adapted from rs3849942 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.