The CAPN3 gene provides instructions for making an enzyme called calpain-3, which is found within muscle cells in structures called sarcomeres. Sarcomeres are the basic unit of muscle contraction. They are made of proteins that generate the mechanical force needed for muscles to contract.
The function of the calpain-3 enzyme is not well understood. Researchers suggest it may help cut (cleave) damaged proteins into shorter segments to facilitate their removal from the sarcomere. Studies have also shown that calpain-3 attaches (binds) to proteins involved in controlling the ability of muscle fibers to stretch (elasticity) and in cell signaling. However, its specific roles in these processes are unknown.
Health Conditions Related to Genetic Changes
Limb-girdle muscular dystrophy
More than 300 mutations in the CAPN3 gene have been identified in people with limb-girdle muscular dystrophy type 2A. This form of limb-girdle muscular dystrophy is also called calpainopathy.
Limb-girdle muscular dystrophy is a group of related disorders characterized by muscle weakness and wasting, particularly in the shoulders, hips, and limbs. CAPN3 gene mutations are the most common cause of limb-girdle muscular dystrophy. These mutations account for approximately 30 percent of limb-girdle muscular dystrophy cases overall, although the percentage varies by specific population.
Most CAPN3 gene mutations change one protein building block (amino acid) in the calpain-3 enzyme. These mutations result in a calpain-3 enzyme that is abnormally short or unstable. Disruption of the enzyme's ability to properly cleave proteins for removal from the sarcomere may allow these waste proteins to accumulate in muscle tissue and become toxic. Other mechanisms have also been suggested to account for the muscle damage that underlies limb-girdle muscular dystrophy in people with CAPN3 gene mutations.More About This Health Condition
Other Names for This Gene
- calcium-activated neutral proteinase 3
- calpain 3, (p94)
- calpain L3
- calpain p94, large [catalytic] subunit
- calpain, large polypeptide L3
- calpain-3 isoform c
- muscle-specific calcium-activated neutral protease 3 large subunit
- new calpain 1
Additional Information & Resources
Tests Listed in the Genetic Testing Registry
Scientific Articles on PubMed
Catalog of Genes and Diseases from OMIM
- Beckmann JS, Spencer M. Calpain 3, the "gatekeeper" of proper sarcomere assembly, turnover and maintenance. Neuromuscul Disord. 2008 Dec;18(12):913-21. doi: 10.1016/j.nmd.2008.08.005. Epub 2008 Oct 29. Citation on PubMed or Free article on PubMed Central
- Broglio L, Tentorio M, Cotelli MS, Mancuso M, Vielmi V, Gregorelli V, Padovani A, Filosto M. Limb-girdle muscular dystrophy-associated protein diseases. Neurologist. 2010 Nov;16(6):340-52. doi: 10.1097/NRL.0b013e3181d35b39. Citation on PubMed
- Duguez S, Bartoli M, Richard I. Calpain 3: a key regulator of the sarcomere? FEBS J. 2006 Aug;273(15):3427-36. doi: 10.1111/j.1742-4658.2006.05351.x. Citation on PubMed
- Guglieri M, Magri F, Comi GP. Molecular etiopathogenesis of limb girdle muscular and congenital muscular dystrophies: boundaries and contiguities. Clin Chim Acta. 2005 Nov;361(1-2):54-79. doi: 10.1016/j.cccn.2005.05.020. Citation on PubMed
- Guglieri M, Straub V, Bushby K, Lochmuller H. Limb-girdle muscular dystrophies. Curr Opin Neurol. 2008 Oct;21(5):576-84. doi: 10.1097/WCO.0b013e32830efdc2. Citation on PubMed
- Kramerova I, Beckmann JS, Spencer MJ. Molecular and cellular basis of calpainopathy (limb girdle muscular dystrophy type 2A). Biochim Biophys Acta. 2007 Feb;1772(2):128-44. doi: 10.1016/j.bbadis.2006.07.002. Epub 2006 Jul 15. Citation on PubMed
- Laval SH, Bushby KM. Limb-girdle muscular dystrophies--from genetics to molecular pathology. Neuropathol Appl Neurobiol. 2004 Apr;30(2):91-105. doi: 10.1111/j.1365-2990.2004.00555.x. Citation on PubMed
- Straub V, Bushby K. The childhood limb-girdle muscular dystrophies. Semin Pediatr Neurol. 2006 Jun;13(2):104-14. doi: 10.1016/j.spen.2006.06.006. Citation on PubMed