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SGCB

sarcoglycan beta

The SGCB gene provides instructions for producing the beta subunit of the sarcoglycan protein complex, critical for maintaining the structural integrity of muscle cells. SGCB is a gene responsible for encoding the beta-sarcoglycan protein, which is an important component of the sarcoglycan complex.

Chromosome 4q12 Autosomal recessive HGNC:10806 Tier C
SGCB 4q12 p arm q arm 4

SGCB is located on the long (q) arm of chromosome 4, at band 4q12. Arm ratio per GRCh38 - banding schematic.

Explore chromosome 4 in the library →

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Clinical tests that include this

Carrier Screening panel
SGCB is 1 of 1,008 genes on this panel
Expanded carrier screening for recessive and X-linked conditions

Overview

The SGCB gene provides the genetic blueprint for beta-sarcoglycan, a key protein within the sarcoglycan complex. This complex is embedded in the membrane surrounding muscle cells and is essential for their structural stability. By interacting with other proteins, SGCB helps to anchor the muscle cell's internal framework to its external environment, preventing damage during muscle activity. Pathogenic changes in SGCB can disrupt this crucial function, leading to various muscular conditions.

What the gene does

The SGCB gene produces the beta-sarcoglycan protein, which integrates into the sarcoglycan protein complex located in the membrane of muscle cells. This complex is vital for the structural integrity of muscle tissue. It functions by binding to and stabilising the larger dystrophin complex, which comprises dystrophins and dystroglycans. The dystrophin complex forms a mechanical connection, linking the cytoskeleton within muscle cells to the extracellular matrix, a network of proteins and molecules outside the cell. This linkage reinforces muscle fibres, reducing potential injury during muscle contraction and relaxation.

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Chromosome location

The SGCB gene is situated on chromosome 4, specifically at position 4q12. This genomic location specifies the precise address of the gene within the human genome. The gene spans a region on the long arm of chromosome 4.

Protein structure

The SGCB gene encodes a protein composed of 318 amino acids. The protein includes a Disordered (Region) spanning amino acids 1-32. This region's lack of fixed three-dimensional structure often enables it to interact with multiple partners and participate in various cellular processes.

Key variants

Genetic variations within the SGCB gene can alter the structure or function of the beta-sarcoglycan protein. Such changes may affect how the protein functions within the sarcoglycan complex that supports muscle cell structure. These variations are typically inherited in an autosomal recessive pattern.

The table below shows the top 10 pathogenic or likely-pathogenic variants currently classified in ClinVar for SGCB.
View all on ClinVar →

Sample of pathogenic variants

10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.

Variant (HGVS) Protein change Classification Evidence Associated condition
c.271C>T
single nucleotide variant
 p.Arg91Cys Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.341C>T
single nucleotide variant
 p.Ser114Phe Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.377_384dup
Duplication
 p.Gly129delinsGlnTer Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.391C>T
single nucleotide variant
 p.Arg131Ter Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.452C>G
single nucleotide variant
 p.Thr151Arg Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.85A>T
single nucleotide variant
 p.Arg29Ter Pathogenic ★★★☆ Autosomal recessive limb-girdle muscular dystrophy
c.165_166del
Deletion
 p.Gly56fs Pathogenic/Likely pathogenic ★★☆☆ Autosomal recessive limb-girdle muscular dystrophy type 2E
c.36_37delinsG
Indel
 p.Ser13fs Pathogenic ★★☆☆ Autosomal recessive limb-girdle muscular dystrophy type 2E
c.518dup
Duplication
 p.Arg174fs Pathogenic/Likely pathogenic ★★☆☆ SGCB-related disorder
c.622-1G>T
single nucleotide variant
 - Pathogenic ★★☆☆ Autosomal recessive limb-girdle muscular dystrophy type 2E

Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.

Associated conditions

Variations in the SGCB gene are associated with inherited muscle conditions, including various forms of limb-girdle muscular dystrophy. Research suggests that pathogenic changes in this gene can lead to muscle disorders affecting skeletal muscle function.

No disease links recorded for this gene in our reference set.

Inheritance pattern

Conditions caused by pathogenic SGCB variants typically follow autosomal recessive inheritance.

♀ Carrier parent 1 altered copy ♂ Carrier parent 1 altered copy Affected Carrier Carrier Unaffected Affected Carrier Unaffected Circles = females · Squares = males

When both parents are carriers, each child has a 25% chance of being affected, 50% of being a carrier, and 25% of being unaffected.

Carrier frequency by population How common is heterozygous SGCB carrier status across ancestry groups?

UK clinical status

The SGCB gene is included in the 'Limb girdle muscular dystrophies, myofibrillar myopathies and distal myopathies' panel (R82) within the NHS Genomic Medicine Service, indicated by its green status, suggesting it is a gene for which there is strong evidence of association with disease.

Green-listed
High evidence · clinically actionable in NHS testing
Included in NHS GMS signed-off panels
Limb girdle muscular dystrophies, myofibrillar myopathies and distal myopathies · R82 NHS GMS →
NHS Genomic Medicine Service Jeen carrier screening

Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory

Frequently asked questions

What is the function of the SGCB gene?

The SGCB gene provides instructions for making beta-sarcoglycan, a component of the sarcoglycan complex. This complex is crucial for maintaining the structural integrity of muscle cells by anchoring them to the surrounding extracellular matrix, protecting them from damage during muscle contraction.

What conditions are associated with changes in the SGCB gene?

Variations in the SGCB gene are associated with inherited muscle disorders, specifically certain forms of limb-girdle muscular dystrophy. Evidence suggests that pathogenic changes in this gene can lead to muscle conditions that affect skeletal muscle function.

How is a condition related to SGCB inherited?

Conditions linked to pathogenic changes in the SGCB gene are typically inherited in an autosomal recessive pattern. This means an individual must inherit two altered copies of the gene, one from each parent, to develop the condition.

References

  1. Broglio L, Tentorio M, Cotelli MS. Limb-girdle muscular dystrophy-associated protein diseases. The neurologist. 2010. PMID: 21150381
  2. Sandonà D, Betto R. Sarcoglycanopathies: molecular pathogenesis and therapeutic prospects. Expert reviews in molecular medicine. 2009. PMID: 19781108
  3. Trabelsi M, Kavian N, Daoud F. Revised spectrum of mutations in sarcoglycanopathies. European journal of human genetics : EJHG. 2008. PMID: 18285821
  4. Guglieri M, Straub V, Bushby K. Limb-girdle muscular dystrophies. Current opinion in neurology. 2008. PMID: 18769252
  5. Meena AK, Sreenivas D, Sundaram C. Sarcoglycanopathies: a clinico-pathological study. Neurology India. 2007. PMID: 17558114
  6. Straub V, Bushby K. The childhood limb-girdle muscular dystrophies. Seminars in pediatric neurology. 2006. PMID: 17027860
  7. Ozawa E, Mizuno Y, Hagiwara Y. Molecular and cell biology of the sarcoglycan complex. Muscle & nerve. 2005. PMID: 15937871
  8. Guglieri M, Magri F, Comi GP. Molecular etiopathogenesis of limb girdle muscular and congenital muscular dystrophies: boundaries and contiguities. Clinica chimica acta; international journal of clinical chemistry. 2005. PMID: 16002060
  9. Fanin M, Angelini C. Defective assembly of sarcoglycan complex in patients with beta-sarcoglycan gene mutations. Study of aneural and innervated cultured myotubes. Neuropathology and applied neurobiology. 2002. PMID: 12060343
  10. Hack AA, Groh ME, McNally EM. Sarcoglycans in muscular dystrophy. Microscopy research and technique. 2000. PMID: 10679964
⚠ Draft content. This page has been flagged for manual clinical review and may contain gaps or inaccuracies. Speak with a qualified healthcare professional before acting on any information here.
Educational content. This page is not medical or genetic advice, is not individually reviewed by a clinician for each reader, and should not replace a consultation with a qualified healthcare professional or genetic counsellor. If you are considering genetic testing or acting on a test result, book a consultation.
Data sources Last updated 11 October 2026. Content compiled from HGNC · MedlinePlus Genetics · ClinGen · Genomics England PanelApp · NHS National Genomic Test Directory · ClinVar · UniProt · AlphaFold .