SGCB

Chr 4AR

sarcoglycan beta

Also known as: A3b, LGMD2E, LGMDR4, SGC

NCBI Gene: 6443ENSG00000163069UniProt: Q16585OMIM: 600900

The protein is a transmembrane component of the dystrophin-glycoprotein complex that stabilizes muscle fiber membranes and links the muscle cytoskeleton to the extracellular matrix. Mutations cause limb-girdle muscular dystrophy type 4 through autosomal recessive inheritance. Loss of functional protein disrupts the structural integrity of the sarcolemma, leading to progressive muscle weakness and degeneration.

OMIMResearchSummary from RefSeq, OMIM, UniProt
DNmechanismARLOEUF 1.471 OMIM phenotype
VCEP Guidelines: Limb Girdle Muscular DystrophyReleased
ClinGen Panel
Clinical Summary— SGCB
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Gene-Disease Validity (ClinGen)
autosomal recessive limb-girdle muscular dystrophy · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
Explore recent and relevant literature in Research Assistant →

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint
1.47LOEUF
pLI 0.000
Z-score 0.42
OE 0.87 (0.53–1.47)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
-0.00Z-score
OE missense 1.00 (0.89–1.13)
178 obs / 177.8 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios
LoF OE0.87 (0.53–1.47)
0≤0.351.4
Missense OE1.00 (0.89–1.13)
0≤0.61.4
Synonymous OE1.16
0≤1.21.6
LoF obs/exp: 10 / 11.5Missense obs/exp: 178 / 177.8Syn Z: -0.98
DN
0.6646th %ile
GOF
0.6151th %ile
LOF
0.4038th %ile

The highest-scoring mechanism for this gene is dominant-negative.

DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

SGCB · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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Full-Text Mentions
NLP-detected gene mentions in article bodies · via PubTator3
PubTator3
Top 5 full-text resultsSearch PubTator3 ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
In a cohort of 961 clinically suspected Duchenne muscular dystrophy patients, 105 were diagnosed to have other muscular dystrophies (OMDs), with LGMD2E (variant SGCB c.544A>C) being the most common.
Karthikeyan P et al.·Mol Genet Genomic Med
2024Open AccessCohort
Identification of a shared, common haplotype segregating with an SGCB c.544 T > G mutation in Indian patients affected with sarcoglycanopathy.
Sanga S et al.·Sci Rep
2023Open AccessCohort
Comprehensive functional characterization of SGCB coding variants predicts pathogenicity in limb-girdle muscular dystrophy type R4/2E.
Li C et al.·J Clin Invest
2023Open AccessFunctional
Large Region of Homozygous (ROH) Identified in Indian Patients with Autosomal Recessive Limb-Girdle Muscular Dystrophy with p.Thr182Pro Variant in SGCB Gene.
Manjunath V et al.·Hum Mutat
2023Open AccessCohort
Antisense Morpholino-Based In Vitro Correction of a Pseudoexon-Generating Variant in the SGCB Gene.
Magri F et al.·Int J Mol Sci
2022Open Access
Top 5 resultsSearch Europe PMC ↗

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients