Reviewed July 2010
What is the official name of the RYR1 gene?
The official name of this gene is “ryanodine receptor 1 (skeletal).”
RYR1 is the gene's official symbol. The RYR1 gene is also known by other names, listed below.
Read more about gene names and symbols on the About page.
What is the normal function of the RYR1 gene?
The RYR1 gene provides instructions for making a protein called ryanodine receptor 1. This protein is part of a family of ryanodine receptors, which form channels that transport positively charged calcium atoms (ions) within cells. Channels made with the ryanodine receptor 1 protein play a critical role in muscles used for movement (skeletal muscles).
For the body to move normally, skeletal muscles must tense (contract) and relax in a coordinated way. Muscle contractions are triggered by the flow of positively charged ions, including calcium, into muscle cells.
When muscles are at rest, calcium ions are stored in a cellular structure called the sarcoplasmic reticulum inside each muscle cell. In response to certain signals, the RYR1 channel releases calcium ions from the sarcoplasmic reticulum into another part of the muscle cell known as a T-tubule. The resulting increase in calcium ion concentration stimulates muscle fibers to contract, allowing the body to move. The process by which certain chemical signals trigger muscle contraction is called excitation-contraction (E-C) coupling.
How are changes in the RYR1 gene related to health conditions?
central core disease - caused by mutations in the RYR1 gene
More than 40 mutations in the RYR1 gene have been identified in people with central core disease (CCD). Most of these mutations affect single protein building blocks (amino acids) in critical regions of the ryanodine receptor 1 protein. These mutations change the structure of the RYR1 channel, which alters the normal flow of stored calcium ions within muscle cells. A disruption in calcium ion release prevents muscles from contracting normally, leading to the muscle weakness characteristic of central core disease.
Researchers have proposed two mechanisms to explain how RYR1 gene mutations underlie muscle weakness in people with central core disease. Some genetic changes cause the RYR1 channel to be "leaky," allowing calcium ions to flow slowly but continually out of the sarcoplasmic reticulum. The leaky channels greatly reduce the amount of stored calcium ions. As a result, not enough calcium ions are available in the sarcoplasmic reticulum to trigger muscle contractions. Muscle weakness results from the inability of skeletal muscles to contract appropriately.
Other RYR1 gene mutations change the structure of the RYR1 channel in a way that impedes the normal flow of calcium ions. Although the sarcoplasmic reticulum stores plenty of these ions, the receptor cannot release them into T-tubules in response to the usual signals. Without enough calcium ions flowing out of the sarcoplasmic reticulum at the appropriate time, muscles cannot contract normally and muscle weakness results. This mechanism is known as E-C uncoupling.
congenital fiber-type disproportion - caused by mutations in the RYR1 gene
At least seven mutations in the RYR1 gene have been found to cause congenital fiber-type disproportion. Some mutations change single amino acids in the ryanodine receptor 1 protein. Other RYR1 gene mutations create a premature stop signal in the instructions for making the receptor, resulting in an abnormally short, nonfunctional protein. Researchers suspect that disruption of the RYR1 channel may play a role in the muscle weakness and other features of congenital fiber-type disproportion, although the role of RYR1 gene mutations in this condition is unclear.
multiminicore disease - caused by mutations in the RYR1 gene
Several mutations in the RYR1 gene have been found to cause atypical forms of multiminicore disease. These mutations change single amino acids in the ryanodine receptor 1 protein, which alters the structure and function of the protein. The effects of these changes are unclear. Some mutations may reduce the amount of ryanodine receptor 1 protein produced by the cell or lead to an unstable version of the protein. Other mutations may interfere with the normal regulation of the RYR1 channel. Researchers believe that some RYR1 gene mutations change the shape of the channel in such a way that calcium ions cannot flow through properly. A disruption in calcium ion transport prevents muscles from contracting normally, leading to the muscle weakness characteristic of multiminicore disease.
malignant hyperthermia - increased risk from variations of the RYR1 gene
At least 30 mutations in the RYR1 gene are known to increase the risk of malignant hyperthermia. Most of these mutations change single amino acids in important regions of the ryanodine receptor 1 protein. These mutations alter the structure of the RYR1 channel, causing it to open more easily and close more slowly in response to certain drugs (particularly some anesthetic gases and a type of muscle relaxant used during surgery). As a result, large amounts of calcium ions are released from the sarcoplasmic reticulum within muscle cells. An overabundance of available calcium ions causes skeletal muscles to contract abnormally, which leads to muscle rigidity in people with malignant hyperthermia. An increase in calcium ion concentration within muscle cells also activates processes that generate heat (leading to increased body temperature) and produce excess acid (leading to acidosis).
Many other changes in the RYR1 gene have been described in people with an increased risk of malignant hyperthermia. It is unclear, however, whether these variations are directly related to malignant hyperthermia risk.
Where is the RYR1 gene located?
Cytogenetic Location: 19q13.1
Molecular Location on chromosome 19: base pairs 38,924,339 to 39,078,203
The RYR1 gene is located on the long (q) arm of chromosome 19 at position 13.1.
More precisely, the RYR1 gene is located from base pair 38,924,339 to base pair 39,078,203 on chromosome 19.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about RYR1?
You and your healthcare professional may find the following resources about RYR1 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
What other names do people use for the RYR1 gene or gene products?
- ryanodine receptor type1
- sarcoplasmic reticulum calcium release channel
- skeletal muscle ryanodine receptor
- Skeletal muscle-type ryanodine receptor
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding RYR1?
The resources on this site should not be used as a substitute for
professional medical care or advice. Users seeking information about
a personal genetic disease, syndrome, or condition should consult with a qualified
See How can I find a genetics professional in my area? in the Handbook.