13-23295429-CT-C

Position:

chr13-23295429-CT-C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PP4PM3PVS1_StrongPP1_Moderate

This summary comes from the ClinGen Evidence Repository: The NM_000231.3: c.525del p.(Phe175LeufsTer20) variant in SGCG is a frameshift variant that is predicted to introduce a premature stop codon. The resulting transcript is predicted to escape nonsense mediated decay but truncate >10% of the protein (PVS1_Strong). This variant has been detected in at least five apparently unrelated patients with autosomal recessive limb girdle muscular dystrophy, including in a homozygous state in at least four individuals (1.0 pt, PMID:16616845, 10993494, 18285821, 10942431; ClinVar SCV001164546.1) (PM3). At least one patient with this variant displayed progressive limb girdle muscle weakness (PP4). While absent gamma-sarcoglycan protein expression has been reported in the skeletal muscle of patients with this variant, detection may be dependent on the antibody used due to the production of a truncated protein (PMID:10993494, 16616845, 10942431). The variant has been reported to segregate with autosomal recessive LGMD in four affected family members from two families (PP1_Moderate; PMID:10942431, ClinVar SCV001164546.1). The highest minor allele frequency of this variant is 0.0002619 (4/15274 genome chromosomes) in the Admixed American population in gnomAD v3.2.1, which is greater than the VCEP threshold (0.00009) for PM2_Supporting (criterion not met). In summary, this variant meets the criteria to be classified as Likely Pathogenic for autosomal recessive limb girdle muscular dystrophy based on the ACMG/AMP criteria applied, as specified by the ClinGen LGMD VCEP (LGMD VCEP specifications version 1.0.0; 01/08/2025): PVS1_Strong, PM3, PP4, PP1_Moderate. LINK:https://erepo.genome.network/evrepo/ui/classification/CA346837/MONDO:0015152/185

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000053 ( 0 hom. )

Consequence

SGCG
NM_000231.3 frameshift

Scores

Not classified

Clinical Significance

Likely pathogenic reviewed by expert panel P:19

Conservation

PhyloP100: 2.68

Variant links:

Genes affected

SGCG (HGNC:10809): (sarcoglycan gamma) This gene encodes gamma-sarcoglycan, one of several sarcolemmal transmembrane glycoproteins that interact with dystrophin. The dystrophin-glycoprotein complex (DGC) spans the sarcolemma and is comprised of dystrophin, syntrophin, alpha- and beta-dystroglycans and sarcoglycans. The DGC provides a structural link between the subsarcolemmal cytoskeleton and the extracellular matrix of muscle cells. Defects in the encoded protein can lead to early onset autosomal recessive muscular dystrophy, in particular limb-girdle muscular dystrophy, type 2C (LGMD2C). [provided by RefSeq, Oct 2008]

SGCG links:

SACS (HGNC:10519): (sacsin molecular chaperone) This gene encodes the sacsin protein, which includes a UbL domain at the N-terminus, a DnaJ domain, and a HEPN domain at the C-terminus. The gene is highly expressed in the central nervous system, also found in skin, skeletal muscles and at low levels in the pancreas. This gene includes a very large exon spanning more than 12.8 kb. Mutations in this gene result in autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), a neurodegenerative disorder characterized by early-onset cerebellar ataxia with spasticity and peripheral neuropathy. The authors of a publication on the effects of siRNA-mediated sacsin knockdown concluded that sacsin protects against mutant ataxin-1 and suggest that "the large multi-domain sacsin protein is able to recruit Hsp70 chaperone action and has the potential to regulate the effects of other ataxia proteins" (Parfitt et al., PubMed: 19208651). A pseudogene associated with this gene is located on chromosome 11. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, May 2013]

SACS links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

PVS1

For more information check the summary or visit ClinGen Evidence Repository.

PM3

For more information check the summary or visit ClinGen Evidence Repository.

PP1

For more information check the summary or visit ClinGen Evidence Repository.

PP4

For more information check the summary or visit ClinGen Evidence Repository.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SGCG	NM_000231.3 link	c.525delT	p.Phe175fs	frameshift_variant	6/8	ENST00000218867.4	NP_000222.2	Q13326

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SGCG	ENST00000218867.4 link	c.525delT	p.Phe175fs	frameshift_variant	6/8	1	NM_000231.3	ENSP00000218867.3		Q13326
SACS	ENST00000683210.1 link	c.2186-6187delA		intron_variant				ENSP00000506739.1		A0A804HHS6

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152134

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00318

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000557

AC:

AN:

251462

Hom.:

AF XY:

0.0000736

AC XY:

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000867

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000967

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000534

AC:

AN:

1461662

Hom.:

Cov.:

AF XY:

0.0000536

AC XY:

AN XY:

727148

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000594

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152252

Hom.:

Cov.:

AF XY:

0.0000806

AC XY:

AN XY:

74440

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000262

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000735

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000868

Hom.:

Bravo

AF:

0.0000453

EpiCase

AF:

0.000164

EpiControl

AF:

0.000119

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:19

Revision: reviewed by expert panel

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2C

Pathogenic:13

Pathogenic, no assertion criteria provided	research	Section for Clinical Neurogenetics, University of Tübingen	Aug 01, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Sep 15, 2014	The Phe175LeufsX20 variant in SGCG has been reported in many individuals with limb girdle muscular dystrophy type 2C (LGMD2C; Noguchi 1995, Boyden 2010, Herson 2012, Schroder 2014, El Kerch 2014). Data from large population studies is insufficient to assess the frequency of this variant. This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 175 and leads to a premature termination codon 20 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Complete loss of SGCG function is an established disease mechanism in LGMD2C. In summary, this variant meets our criteria to be classified as pathogenic for LGMD2C in an autosomal recessive manner. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 23, 2025	This sequence change creates a premature translational stop signal (p.Phe175Leufs*20) in the SGCG gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SGCG are known to be pathogenic (PMID: 18285821). This variant is present in population databases (rs765500509, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with limb girdle muscular dystrophy (PMID: 7481775, 12040521, 22240777, 23929688, 24552312). ClinVar contains an entry for this variant (Variation ID: 189243). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 14, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 08, 2021	- -
Pathogenic, criteria provided, single submitter	research	Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard	Dec 03, 2018	The homozygous p.Phe175LeufsTer20 variant in SGCG was identified by our study in five individuals (four siblings and one unrelated individual) with limb-girdle muscular dystrophy (LGMD). This variant has been identified in 0.006092% (15/246240) of chromosomes in the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs765500509). Although this variant has been seen in the general population, the frequency is low enough to be consistent with a recessive carrier frequency. This variant is predicted to cause a frameshift, which alters the protein's amino acid sequence beginning at position 175 and leads to a premature termination codon 20 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the SGCG gene is an established disease mechanism in autosomal recessive LGMD. This variant has also been reported in ClinVar (Variation ID: 189243). In summary, this variant meets criteria to be classified as pathogenic for LGMD in an autosomal recessive manner based on the predicted impact of the variant and multiple reports in ClinVar. ACMG/AMP Criteria applied: PM2, PVS1, PP1 (Richards 2015). -
Pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	Nov 30, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	3billion, Medical Genetics	May 22, 2022	The variant is observed at an extremely low frequency in the gnomAD v2.1.1 dataset (total allele frequency: 0.006%). Frameshift: predicted to result in a loss or disruption of normal protein function through nonsense-mediated decay (NMD) or protein truncation. Multiple pathogenic variants are reported downstream of the variant. The variant has been reported at least twice as pathogenic with clinical assertions and evidence for the classification (ClinVar ID: VCV000189243 / PMID: 7481775). Therefore, this variant is classified as pathogenic according to the recommendation of ACMG/AMP guideline. -
Pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Aug 12, 2000	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 30, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre	Mar 26, 2024	- -
Pathogenic, no assertion criteria provided	clinical testing	Counsyl	Feb 22, 2017	- -

not provided

Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Dec 29, 2021	Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 11693784, 18285821, 22367371, 17994539, 16832103, 23929688, 7481775, 16616845, 15954112, 14678800, 26404900, 25252238, 16916601, 22240777, 24552312, 12040521, 27759885, 30919934, 31130284, 31980526, 31127727, 8900232, 20623375, 19770540, 10942431, 32214227, 25214167, 32528171, 31589614) -
Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Sep 01, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 26, 2016	- -
Pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Dec 19, 2014	The variant results in a shift of the reading frame, and is therefore predicted to result in the loss of a functional protein. The frequency of this variant in the general population is consistent with pathogenicity. Found in multiple individuals with expected phenotype for this gene. -

Autosomal recessive limb-girdle muscular dystrophy

Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

ClinGen Limb Girdle Muscular Dystrophy Variant Curation Expert Panel, ClinGen

Jan 08, 2025

The NM_000231.3: c.525del p.(Phe175LeufsTer20) variant in SGCG is a frameshift variant that is predicted to introduce a premature stop codon. The resulting transcript is predicted to escape nonsense mediated decay but truncate >10% of the protein (PVS1_Strong). This variant has been detected in at least five apparently unrelated patients with autosomal recessive limb girdle muscular dystrophy, including in a homozygous state in at least four individuals (1.0 pt, PMID: 16616845, 10993494, 18285821, 10942431; ClinVar SCV001164546.1) (PM3). At least one patient with this variant displayed progressive limb girdle muscle weakness (PP4). While absent gamma-sarcoglycan protein expression has been reported in the skeletal muscle of patients with this variant, detection may be dependent on the antibody used due to the production of a truncated protein (PMID: 10993494, 16616845, 10942431). The variant has been reported to segregate with autosomal recessive LGMD in four affected family members from two families (PP1_Moderate; PMID: 10942431, ClinVar SCV001164546.1). The highest minor allele frequency of this variant is 0.0002619 (4/15274 genome chromosomes) in the Admixed American population in gnomAD v3.2.1, which is greater than the VCEP threshold (0.00009) for PM2_Supporting (criterion not met). In summary, this variant meets the criteria to be classified as Likely Pathogenic for autosomal recessive limb girdle muscular dystrophy based on the ACMG/AMP criteria applied, as specified by the ClinGen LGMD VCEP (LGMD VCEP specifications version 1.0.0; 01/08/2025): PVS1_Strong, PM3, PP4, PP1_Moderate. -

SGCG-related congenital myopathy

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

research

Muscle and Diseases Team, Institut de Génétique et Biologie Moléculaire et Cellulaire

Mar 01, 2024

PVS1+PM2 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over