Genetic variant
rs202027758 a variant in the GYG1 gene
rs202027758 is a single-letter difference in the GYG1 gene, on chromosome 3. ClinVar, the public archive of variant interpretations, lists it as conflicting interpretations: laboratories that have assessed it do not agree on whether it matters. It has been reported in connection with Glycogen storage disease XV and Polyglucosan body myopathy type 2, 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 rs202027758 is the catalogue number of one of them, in the GYG1 gene. Which letters you carry there — one copy from each parent — is your genotype.
GYG1 (glycogenin 1): This gene encodes a member of the glycogenin family. Glycogenin is a glycosyltransferase that catalyzes the formation of a short glucose polymer from uridine diphosphate glucose in an autoglucosylation reaction. This reaction is followed by elongation and branching of the polymer, catalyzed by glycogen synthase and branching enzyme, to form glycogen. This gene is expressed in muscle and other tissues.
Gene description from NCBI Gene
Why might it matter?
ClinVar records this variant as conflicting interpretations, meaning laboratories that have assessed it do not agree on whether it matters. 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
- Glycogen storage disease XV
- Polyglucosan body myopathy type 2
- GYG1-related disorder
- Inborn genetic diseases
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 rs202027758, 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
- rs202027758
- Gene
- GYG1
- Position
- chr3:149026921
- ClinVar classification
- Conflicting classifications of pathogenicity
Sources
- dbSNP: rs202027758 — the reference record
- ClinVar — clinical interpretations submitted by laboratories
- SNPedia — community-written summaries
- NCBI Gene: GYG1
- Ensembl: GYG1