rs28930068

A SNP in the CACNA1S gene on chromosome 1. Its most notable genotype is C;T: Malignant Hyperthermia susceptibility

Gene
CACNA1S
Location
Chr 1201,053,538 (GRCh38)
Highest magnitude
6.6Very important
Tested on
23andMe, AncestryDNA

Genotypes

Plus strand, as in 23andMe and AncestryDNA files.

  1. T;TBadHypokalemic periodic paralysis riskVery important · 5.0
  2. C;TMost notableBadMalignant Hyperthermia susceptibilityVery important · 6.6
  3. C;CGoodcommon in clinvarTypical · 0.0

SNPedia records rs28930068 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.

Conditions, medicines and genes

Other CACNA1S SNPs

All CACNA1S SNPs

Notes

From SNPedia

Notes

rs28930068, also known as R1239H or Arg1239His, is a SNP in the CACNA1S gene on chromosome 1. Carrying one copy of a rs28930068(A) allele is sufficient to result in patients with hypokalemic periodic paralysis, type 1. This variant meets the criteria published in 2013 by the ACMG regarding incidental findings in exome or genome sequencing, as a variant that they do recommend informing a patient about.

T;T

Hypokalemic periodic paralysis (hypoKPP) is an autosomal dominant skeletal muscle disorder, so carriers of even one rs28930068(G) allele are at risk for this disorder.

Source and license

Adapted from rs28930068 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 Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice.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.