13-23295429-CT-C

Variant names:

• chr13-23295429-CT-C
• rs786204786
• NM_000231.3:c.525delT

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM3 PVS1_Strong PP1_Moderate PP4

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
• Clinical Significance: Likely pathogenic reviewed by expert panel P:20
• Conservation: PhyloP100: 2.68
• Publications: 27 publications found

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]

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 Gene-Disease associations (from GenCC):

• Charlevoix-Saguenay spastic ataxia

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, PanelApp Australia, G2P, Myriad Women’s Health, Orphanet

ACMG classification

Our verdict: Likely_pathogenic. The variant received 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.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000231.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SGCG	NM_000231.3	MANE Select	c.525delT	p.Phe175LeufsTer20	frameshift	Exon 6 of 8	NP_000222.2	Q13326
	SGCG	NM_001378244.1		c.579delT	p.Phe193LeufsTer20	frameshift	Exon 6 of 8	NP_001365173.1
	SGCG	NM_001378245.1		c.525delT	p.Phe175LeufsTer20	frameshift	Exon 7 of 9	NP_001365174.1	Q13326

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SGCG	ENST00000218867.4	TSL:1 MANE Select	c.525delT	p.Phe175LeufsTer20	frameshift	Exon 6 of 8	ENSP00000218867.3	Q13326
	SGCG	ENST00000942469.1		c.525delT	p.Phe175LeufsTer80	frameshift	Exon 6 of 9	ENSP00000612528.1
	SGCG	ENST00000876364.1		c.525delT	p.Phe175LeufsTer20	frameshift	Exon 7 of 9	ENSP00000546423.1

Frequencies

GnomAD3 genomes AF: 0.0000657 AC: 10 AN: 152134 Hom.: 0 Cov.: 33

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

GnomAD2 exomes AF: 0.0000557 AC: 14 AN: 251462 AF XY: 0.0000736

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000967

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000534 AC: 78 AN: 1461662 Hom.: 0 Cov.: 30 AF XY: 0.0000536 AC XY: 39 AN XY: 727148

African (AFR) AF: 0.00 AC: 0 AN: 33476

American (AMR) AF: 0.0000671 AC: 3 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39692

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.000347 AC: 2 AN: 5768

European-Non Finnish (NFE) AF: 0.0000594 AC: 66 AN: 1111810

Other (OTH) AF: 0.000116 AC: 7 AN: 60388

GnomAD4 genome AF: 0.0000657 AC: 10 AN: 152252 Hom.: 0 Cov.: 33 AF XY: 0.0000806 AC XY: 6 AN XY: 74440

African (AFR) AF: 0.00 AC: 0 AN: 41540

American (AMR) AF: 0.000262 AC: 4 AN: 15294

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5182

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00342 AC: 1 AN: 292

European-Non Finnish (NFE) AF: 0.0000735 AC: 5 AN: 68012

Other (OTH) AF: 0.00 AC: 0 AN: 2114

Alfa AF: 0.0000868 Hom.: 0

Bravo AF: 0.0000453

EpiCase AF: 0.000164

EpiControl AF: 0.000119

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: reviewed by expert panel

Pathogenic	VUS	Benign	Condition
14	-	-	Autosomal recessive limb-girdle muscular dystrophy type 2C (14)
4	-	-	not provided (4)
1	-	-	Autosomal recessive limb-girdle muscular dystrophy (1)
1	-	-	SGCG-related congenital myopathy (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.7
Mutation Taster		=3/197	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs786204786; hg19: chr13-23869568;