Reviewed April 2011
What is the official name of the SGCA gene?
The official name of this gene is “sarcoglycan, alpha (50kDa dystrophin-associated glycoprotein).”
SGCA is the gene's official symbol. The SGCA gene is also known by other names, listed below.
What is the normal function of the SGCA gene?
The SGCA gene provides instructions for making the alpha component (subunit) of a group of proteins called the sarcoglycan protein complex. The sarcoglycan protein complex is located in the membrane surrounding muscle cells. It helps maintain the structure of muscle tissue by attaching (binding) to and stabilizing the dystrophin complex, which is made up of proteins called dystrophins and dystroglycans. The large dystrophin complex strengthens muscle fibers and protects them from injury as muscles tense (contract) and relax. It acts as an anchor, connecting each muscle cell's structural framework (cytoskeleton) with the lattice of proteins and other molecules outside the cell (extracellular matrix).
How are changes in the SGCA gene related to health conditions?
- limb-girdle muscular dystrophy - caused by mutations in the SGCA gene
More than 70 mutations in the SGCA gene have been identified in people with limb-girdle muscular dystrophy type 2D. Limb-girdle muscular dystrophy is a group of related disorders characterized by muscle weakness and wasting, particularly in the shoulders, hips, and limbs. Forms of limb-girdle muscular dystrophy caused by gene mutations that affect the sarcoglycan complex are called sarcoglycanopathies.
The most common SGCA gene mutation occurs in about one-third of people with limb-girdle muscular dystrophy type 2D. This mutation replaces the protein building block (amino acid) arginine with the amino acid cysteine at position 77 in the alpha-sarcoglycan protein, written as Arg77Cys or R77C. The rest of the known SGCA gene mutations are specific to individual families or certain populations.
SGCA gene mutations may prevent the sarcoglycan complex from forming or from binding to and stabilizing the dystrophin complex. Problems with these complexes reduce the strength and resilience of muscle fibers and result in the signs and symptoms of limb-girdle muscular dystrophy.
Where is the SGCA gene located?
Cytogenetic Location: 17q21
Molecular Location on chromosome 17: base pairs 50,165,974 to 50,175,931
The SGCA gene is located on the long (q) arm of chromosome 17 at position 21.
More precisely, the SGCA gene is located from base pair 50,165,974 to base pair 50,175,931 on chromosome 17.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
Where can I find additional information about SGCA?
You and your healthcare professional may find the following resources about SGCA helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
- PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=%28%28SGCA%5BTIAB%5D%29%20OR%20%28sarcoglycan,%20alpha%5BTIAB%5D%29%29%20OR%20%28%2850%20kDa%20dystrophin-associated%20glycoprotein%5BTIAB%5D%29%20OR%20%2850-DAG%5BTIAB%5D%29%20OR%20%2850DAG%5BTIAB%5D%29%20OR%20%28adhalin%5BTIAB%5D%29%20OR%20%28alpha-sarcoglycan%5BTIAB%5D%29%20OR%20%28alpha-SG%5BTIAB%5D%29%20OR%20%28DAG2%5BTIAB%5D%29%20OR%20%28LGMD2D%5BTIAB%5D%29%29%20AND%20%28%28Genes%5BMH%5D%29%20OR%20%28Genetic%20Phenomena%5BMH%5D%29%29%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D%20AND%20%22last%20720%20days%22%5Bdp%5D)
- OMIM - Genetic disorder catalog (http://omim.org/entry/600119)
Research Resources - Tools for researchers
- Atlas of Genetics and Cytogenetics in Oncology and Haematology (http://atlasgeneticsoncology.org/Genes/GC_SGCA.html)
- HGNC Gene Symbol Report (http://www.genenames.org/cgi-bin/gene_symbol_report?q=data/hgnc_data.php&hgnc_id=10805)
- NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/6442)
What other names do people use for the SGCA gene or gene products?
- 50 kDa dystrophin-associated glycoprotein
- 50kD DAG
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
What glossary definitions help with understanding SGCA?
amino acid ;
extracellular matrix ;
muscle cell ;
muscle cells ;
muscular dystrophy ;
You may find definitions for these and many other terms in the Genetics Home Reference
- 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. Review. (http://www.ncbi.nlm.nih.gov/pubmed/21150381?dopt=Abstract)
- 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. Review. (http://www.ncbi.nlm.nih.gov/pubmed/16002060?dopt=Abstract)
- Guglieri M, Straub V, Bushby K, Lochmüller H. Limb-girdle muscular dystrophies. Curr Opin Neurol. 2008 Oct;21(5):576-84. doi: 10.1097/WCO.0b013e32830efdc2. Review. (http://www.ncbi.nlm.nih.gov/pubmed/18769252?dopt=Abstract)
- Hack AA, Groh ME, McNally EM. Sarcoglycans in muscular dystrophy. Microsc Res Tech. 2000 Feb 1-15;48(3-4):167-80. Review. (http://www.ncbi.nlm.nih.gov/pubmed/10679964?dopt=Abstract)
- Laval SH, Bushby KM. Limb-girdle muscular dystrophies--from genetics to molecular pathology. Neuropathol Appl Neurobiol. 2004 Apr;30(2):91-105. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15043707?dopt=Abstract)
- Meena AK, Sreenivas D, Sundaram C, Rajasekhar R, Sita JS, Borgohain R, Suvarna A, Kaul S. Sarcoglycanopathies: a clinico-pathological study. Neurol India. 2007 Apr-Jun;55(2):117-21. (http://www.ncbi.nlm.nih.gov/pubmed/17558114?dopt=Abstract)
- NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/6442)
- Ozawa E, Mizuno Y, Hagiwara Y, Sasaoka T, Yoshida M. Molecular and cell biology of the sarcoglycan complex. Muscle Nerve. 2005 Nov;32(5):563-76. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15937871?dopt=Abstract)
- Sandonà D, Betto R. Sarcoglycanopathies: molecular pathogenesis and therapeutic prospects. Expert Rev Mol Med. 2009 Sep 28;11:e28. doi: 10.1017/S1462399409001203. Review. (http://www.ncbi.nlm.nih.gov/pubmed/19781108?dopt=Abstract)
- Straub V, Bushby K. The childhood limb-girdle muscular dystrophies. Semin Pediatr Neurol. 2006 Jun;13(2):104-14. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17027860?dopt=Abstract)
- Trabelsi M, Kavian N, Daoud F, Commere V, Deburgrave N, Beugnet C, Llense S, Barbot JC, Vasson A, Kaplan JC, Leturcq F, Chelly J. Revised spectrum of mutations in sarcoglycanopathies. Eur J Hum Genet. 2008 Jul;16(7):793-803. doi: 10.1038/ejhg.2008.9. Epub 2008 Feb 20. (http://www.ncbi.nlm.nih.gov/pubmed/18285821?dopt=Abstract)
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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.