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Genetics Library / Genes / GYS1

GENE REFERENCE / HGNC:4706

GYS1

glycogen synthase 1

protein-coding gene19q13.33Gene information

What does this gene do?

The GYS1 gene provides instructions for making an enzyme called muscle glycogen synthase. Muscle glycogen synthase is produced in most cells but is most abundant in heart (cardiac) muscle and muscles used for movement (skeletal muscles). Muscle glycogen synthase helps link together molecules of the simple sugar glucose to form the complex sugar glycogen, which is a major source of stored energy in the body. Most glucose that is taken in from food is stored as glycogen in muscle cells. During contractions of the cardiac muscle or rapid or sustained movement of skeletal muscle, glycogen stored in muscle cells is broken down to supply the cells with energy.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2014-01.

Related condition topics

MedlinePlus mentions this gene in the condition pages below. These links alone do not show that the gene causes a condition.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

ConditionInheritanceEvidence
glycogen storage disease due to muscle and heart glycogen synthase deficiencyMONDO:0012693 · Evaluated 2024-02-12Autosomal recessiveDefinitiveGeneral Inborn Errors of Metabolism Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles
792
Submissions for variants in or overlapping this gene
1,141
Submissions explicitly reporting this gene
1,117
Alleles reported pathogenic / likely pathogenic
51
VariationIDs with uncertain significance
349
VariationIDs with conflicting classifications
22

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about GYS1?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 51 alleles in GYS1 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in GYS1.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

Sources and dates

The source information on this page last changed on 2026-10-10.

HGNC Source details

Open source record ↗

Source release: Fri, 09 Oct 2026 13:40:45 GMT
Source record updated: 2023-01-20

SHA-256: e4cd9c6d7120051b80e5e61d2aeb98bd6a541ddd21f428a6eab922c11242e053

MedlinePlus Source details

Open source record ↗

Source release: Sat, 10 Oct 2026 05:16:07 GMT
Source publication: 2020-08-18
Source review: 2014-01

SHA-256: fdc8bd614310c12718379cef6569962e5d0e791cecabcc355b53a72816ac263a

ClinVar Source details

Open source record ↗

Source release: Sun, 04 Oct 2026 13:15:29 GMT

SHA-256: 126d9e5bded1d43c0380ac6684c86f9aab056d2ff2be93d743e408ed917ae558

ClinGen Source details

Open source record ↗

Source release: Sat, 10 Oct 2026 09:49:14 GMT

SHA-256: 5bbc9404c72cc21d80e36ea4c49380231755850af5c34064262adceb74881af6

About the library sources · Latest validated release · Record ff209e52abfd