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Gamma-sarcoglycan is a protein that in humans is encoded by the SGCG gene.[1][2] The α to δ-sarcoglycans are expressed predominantly (β) or exclusively (α, γ and δ) in striated muscle.[3] A mutation in any of the sarcoglycan genes may lead to a secondary deficiency of the other sarcoglycan proteins, presumably due to destabilisation of the sarcoglycan complex.[4] The disease-causing mutations in the α to δ genes cause disruptions within the dystrophin-associated protein (DAP) complex in the muscle cell membrane.[5] The transmembrane components of the DAP complex link the cytoskeleton to the extracellular matrix in adult muscle fibres,[6] and are essential for the preservation of the integrity of the muscle cell membrane.[7]


Gamma-sarcoglycan is one of several sarcolemmal transmembrane glycoproteins that interact with dystrophin, probably to provide a link between the membrane associated cytoskeleton and the extracellular matrix. Defects in the protein can lead to early onset autosomal recessive muscular dystrophy, in particular limb-girdle muscular dystrophy, type 2C (LGMD2C).[2]



Human SGCG gene maps to chromosome 13 at q12, spans over 100 kb of DNA and includes 8 exons.[8]


Gamma-sarcoglycan is a type II transmembrane protein and consists of 291 amino acids. It has a 35 amino acid intracellular N-terminal region, a 25 amino acid single transmembrane domain, and a 231 amino acid extra-cellular C-terminus.[4]

Clinical significance

Sarcoglycanopathies are autosomal recessive limb girdle muscular dystrophies (LGMDs) caused by mutations in any of the four sarcoglycan genes: α (LGMD2D), β (LGMD2E), γ (LGMD2C) and δ (LGMD2F).[3] Severe childhood autosomal recessive muscular dystrophy (SCARMD) is a progressive muscle-wasting disorder that segregates with microsatellite markers at γ-sarcoglycan gene. Mutations in the γ-sarcoglycan gene were first described in the Maghreb countries of North Africa,[9] where γ-sarcoglycanopathy has a higher than usual incidence. One common mutation, Δ-521T, which causes a severe phenotype, occurs both in the Maghreb population and in other countries.[8] A Cys283Tyr mutation has been identified in the Gypsy population causing a severe phenotype and a Leu193Ser mutation which causes a mild phenotype.[1][10]


SGCG has been shown to interact with FLNC.[11][12]


  1. 1.0 1.1 Piccolo F, Jeanpierre M, Leturcq F, Dodé C, Azibi K, Toutain A, Merlini L, Jarre L, Navarro C, Krishnamoorthy R, Tomé FM, Urtizberea JA, Beckmann JS, Campbell KP, Kaplan JC (Dec 1996). "A founder mutation in the gamma-sarcoglycan gene of gypsies possibly predating their migration out of India". Human Molecular Genetics. 5 (12): 2019–22. doi:10.1093/hmg/5.12.2019. PMID 8968757.
  2. 2.0 2.1 "Entrez Gene: SGCG sarcoglycan, gamma (35kDa dystrophin-associated glycoprotein)".
  3. 3.0 3.1 Noguchi S, McNally EM, Ben Othmane K, Hagiwara Y, Mizuno Y, Yoshida M, Yamamoto H, Bönnemann CG, Gussoni E, Denton PH, Kyriakides T, Middleton L, Hentati F, Ben Hamida M, Nonaka I, Vance JM, Kunkel LM, Ozawa E (Nov 1995). "Mutations in the dystrophin-associated protein gamma-sarcoglycan in chromosome 13 muscular dystrophy". Science. 270 (5237): 819–22. doi:10.1126/science.270.5237.819. PMID 7481775.
  4. 4.0 4.1 Nowak KJ, Walsh P, Jacob RL, Johnsen RD, Peverall J, McNally EM, Wilton SD, Kakulas BA, Laing NG (Feb 2000). "Severe gamma-sarcoglycanopathy caused by a novel missense mutation and a large deletion". Neuromuscular Disorders. 10 (2): 100–7. doi:10.1016/s0960-8966(99)00063-2. PMID 10714584.
  5. Vainzof M, Passos-Bueno MR, Canovas M, Moreira ES, Pavanello RC, Marie SK, Anderson LV, Bonnemann CG, McNally EM, Nigro V, Kunkel LM, Zatz M (Dec 1996). "The sarcoglycan complex in the six autosomal recessive limb-girdle muscular dystrophies". Human Molecular Genetics. 5 (12): 1963–9. doi:10.1093/hmg/5.12.1963. PMID 8968750.
  6. Ettinger AJ, Feng G, Sanes JR (Dec 1997). "epsilon-Sarcoglycan, a broadly expressed homologue of the gene mutated in limb-girdle muscular dystrophy 2D". The Journal of Biological Chemistry. 272 (51): 32534–8. doi:10.1074/jbc.272.51.32534. PMID 9405466.
  7. Holt KH, Campbell KP (Dec 1998). "Assembly of the sarcoglycan complex. Insights for muscular dystrophy". The Journal of Biological Chemistry. 273 (52): 34667–70. doi:10.1074/jbc.273.52.34667. PMID 9856984.
  8. 8.0 8.1 McNally EM, Duggan D, Gorospe JR, Bönnemann CG, Fanin M, Pegoraro E, Lidov HG, Noguchi S, Ozawa E, Finkel RS, Cruse RP, Angelini C, Kunkel LM, Hoffman EP (Nov 1996). "Mutations that disrupt the carboxyl-terminus of gamma-sarcoglycan cause muscular dystrophy". Human Molecular Genetics. 5 (11): 1841–7. doi:10.1093/hmg/5.11.1841. PMID 8923014.
  9. el Kerch F, Sefiani A, Azibi K, Boutaleb N, Yahyaoui M, Bentahila A, Vinet MC, Leturcq F, Bachner L, Beckmann J (Apr 1994). "Linkage analysis of families with severe childhood autosomal recessive muscular dystrophy in Morocco indicates genetic homogeneity of the disease in north Africa". Journal of Medical Genetics. 31 (4): 342–3. doi:10.1136/jmg.31.4.342. PMC 1049813. PMID 8071965.
  10. van der Kooi AJ, de Visser M, van Meegen M, Ginjaar HB, van Essen AJ, Jennekens FG, Jongen PJ, Leschot NJ, Bolhuis PA (Jun 1998). "A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy". Neuromuscular Disorders. 8 (5): 305–8. doi:10.1016/s0960-8966(98)00040-6. PMID 9673983.
  11. Guyon JR, Kudryashova E, Potts A, Dalkilic I, Brosius MA, Thompson TG, Beckmann JS, Kunkel LM, Spencer MJ (October 2003). "Calpain 3 cleaves filamin C and regulates its ability to interact with gamma- and delta-sarcoglycans". Muscle Nerve. 28 (4): 472–83. doi:10.1002/mus.10465. PMID 14506720.
  12. Thompson TG, Chan YM, Hack AA, Brosius M, Rajala M, Lidov HG, McNally EM, Watkins S, Kunkel LM (January 2000). "Filamin 2 (FLN2): A muscle-specific sarcoglycan interacting protein". J. Cell Biol. 148 (1): 115–26. doi:10.1083/jcb.148.1.115. PMC 3207142. PMID 10629222.

Further reading

External links