rs121912810
A SNP in the CLCN1 gene on chromosome 7. Its most notable genotype is C;T: Myotonia congenita; Thomsen's disease; quite variable in degree
- Gene
- CLCN1
- Location
- Chr 7143,321,718 (GRCh38)
- Highest magnitude
- 4.0Very important
- Tested on
- AncestryDNA
Genotypes
As shown in 23andMe and AncestryDNA files.
- C;CGoodcommon in clinvar
- C;TMost notableBadMyotonia congenita; Thomsen's disease; quite variable in degree
On SNPedia: (C;C), (C;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.
Related
Conditions, medicines and genes
Other CLCN1 SNPs
- i5003255T;TMyotonia congenita; quite variable in degreeVery important
- i5003257A;AMyotonia congenita; degree varies widelyVery important
- i5003258A;AMyotonia congenita; quite variable in degreeVery important
- rs55960271T;TMyotonia congenita; quite variable in degreeVery important
- rs80356684T;TMyotonia congenita; quite variable in degreeVery important
- rs80356687T;TMyotonia congenita; quite variable in degreeVery important
- rs80356688T;TMyotonia congenita; quite variable in degreeVery important
- rs80356692A;AMyotonia congenita; quite variable in degreeVery important
Notes
From SNPedia
Notes
rs121912810, also known as p.Ser189Phe, is a mutation in the CLCN1 gene on chromosome 7. Acting in an autosomal dominant manner, the rs121912810(T) allele is considered to cause Thomsen's myotonia congenita; see also OMIM 118425.0018 Note that 23andMe refers to this SNP as i5003253.
C;T
See discussion at myotonia congenita
Source and license
Adapted from rs121912810 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.