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Genetics Home Reference: your guide to understanding genetic conditions
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SGCB

Reviewed April 2011

What is the official name of the SGCB gene?

The official name of this gene is “sarcoglycan, beta (43kDa dystrophin-associated glycoprotein).”

SGCB is the gene's official symbol. The SGCB gene is also known by other names, listed below.

What is the normal function of the SGCB gene?

The SGCB gene provides instructions for making the beta 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 SGCB gene related to health conditions?

limb-girdle muscular dystrophy - caused by mutations in the SGCB gene

Approximately 50 mutations in the SGCB gene have been identified in people with limb-girdle muscular dystrophy type 2E. Limb-girdle muscular dystrophy is a group of related disorders characterized by muscle weakness and wasting, particularly in the shoulders, hips, and limbs.

Some people with limb-girdle muscular dystrophy type 2E also develop a heart condition called dilated cardiomyopathy. Dilated cardiomyopathy is a form of heart disease that enlarges and weakens the heart (cardiac) muscle, preventing it from pumping blood efficiently. Dilated cardiomyopathy progresses rapidly and is life-threatening in many cases.

Forms of limb-girdle muscular dystrophy caused by gene mutations that affect the sarcoglycan complex are called sarcoglycanopathies. SGCB 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 SGCB gene located?

Cytogenetic Location: 4q12

Molecular Location on chromosome 4: base pairs 52,020,694 to 52,038,318

The SGCB gene is located on the long (q) arm of chromosome 4 at position 12.

The SGCB gene is located on the long (q) arm of chromosome 4 at position 12.

More precisely, the SGCB gene is located from base pair 52,020,694 to base pair 52,038,318 on chromosome 4.

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 SGCB?

You and your healthcare professional may find the following resources about SGCB 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 SGCB gene or gene products?

  • 43DAG
  • 43 kDa dystrophin-associated glycoprotein
  • A3b
  • beta-sarcoglycan
  • beta-SG
  • LGMD2E
  • SG-beta
  • SGC
  • SGCB_HUMAN

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 SGCB?

cardiac ; cardiomyopathy ; cell ; cytoskeleton ; dilated ; extracellular ; extracellular matrix ; gene ; injury ; muscle cell ; muscle cells ; muscular dystrophy ; protein ; resilience ; subunit ; tissue ; wasting

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (/glossary).

References

  • 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)
  • Fanin M, Angelini C. Defective assembly of sarcoglycan complex in patients with beta-sarcoglycan gene mutations. Study of aneural and innervated cultured myotubes. Neuropathol Appl Neurobiol. 2002 Jun;28(3):190-9. (http://www.ncbi.nlm.nih.gov/pubmed/12060343?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)
  • 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/6443)
  • 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 healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: April 2011
Published: May 18, 2015