Genetic variant
rs121909259 a variant in the CASR gene
rs121909259 is a single-letter difference in the CASR gene, on chromosome 3. ClinVar, the public archive of variant interpretations, lists it as pathogenic: able to cause or contribute to disease. It has been reported in connection with Familial hypocalciuric hypercalcemia 1 and Neonatal severe primary hyperparathyroidism, among others. Carrying it does not, on its own, mean you have or will develop any condition.
What is this?
Your DNA is a long sequence of four letters. At a few million positions, people commonly differ by a single letter; each of those positions is called a SNP (“snip”), and rs121909259 is the catalogue number of one of them, in the CASR gene. Which letters you carry there — one copy from each parent — is your genotype.
CASR (calcium sensing receptor): The protein encoded by this gene is a plasma membrane G protein-coupled receptor that senses small changes in circulating calcium concentration. The encoded protein couples this information to intracellular signaling pathways that modify parathyroid hormone secretion or renal cation handling, and thus this protein plays an essential role in maintaining mineral ion homeostasis.
Gene description from NCBI Gene
Why might it matter?
ClinVar records this variant as pathogenic, meaning able to cause or contribute to disease. A classification describes the variant, not you: what it means for one person depends on their genotype, their family history and often on other genes and circumstances.
Conditions it has been reported with
- Familial hypocalciuric hypercalcemia 1
- Neonatal severe primary hyperparathyroidism
- Autosomal dominant hypocalcemia 1
- Familial hypocalciuric hypercalcemia
Listed in ClinVar submissions for this variant. Being listed is a report of an association, not a statement that the variant causes the condition in any given person.
Do I have this variant?
If you have taken a consumer DNA test (23andMe, AncestryDNA and similar), you can download its raw data file and check. Create a free account, upload the file, and this page will show the letters you carry at rs121909259, if your test read this position.
Connect this with your blood results
A gene is a fixed instruction; a blood test shows what your body is doing now. CheckMyBloods reads the two side by side, so a variant can be set against the markers it could plausibly affect.
Blood markers do not diagnose a genetic condition, and a variant does not explain a blood result on its own. Together, with symptoms and family history, they give a clinician context.
What should I do next?
- Find out whether you carry it. Reading about a variant says nothing about you until you know your genotype.
- Put it in context. Add your blood results, so the variant can be read against what your body is doing.
- Ask questions. Dr. Hemsworth, our AI assistant, can explain this variant and your results in plain English.
- Take anything that worries you to a professional. A GP or genetic counsellor can order a confirmatory test and interpret it with your history.
This page is general information drawn from public research databases. It cannot diagnose anything, and it is not a substitute for advice from a doctor or genetic counsellor who knows your history.
Technical details
- dbSNP ID
- rs121909259
- Gene
- CASR
- Position
- chr3:122261924
- ClinVar classification
- Pathogenic
Sources
- dbSNP: rs121909259 — the reference record
- ClinVar — clinical interpretations submitted by laboratories
- SNPedia — community-written summaries
- NCBI Gene: CASR
- Ensembl: CASR