13-23203740-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000231.3(SGCG):c.46G>C(p.Glu16Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000347 in 1,613,988 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000036 (0 hom.)
• Consequence: SGCG NM_000231.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.37

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a chain Gamma-sarcoglycan (size 290) in uniprot entity SGCG_HUMAN there are 38 pathogenic changes around while only 8 benign (83%) in NM_000231.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.09949571).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SGCG	NM_000231.3	c.46G>C	p.Glu16Gln	missense_variant	2/8	ENST00000218867.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SGCG	ENST00000218867.4	c.46G>C	p.Glu16Gln	missense_variant	2/8	1	NM_000231.3	P1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152216 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000588

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000239 AC: 6 AN: 251012 Hom.: 0 AF XY: 0.0000295 AC XY: 4 AN XY: 135684

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.0000529

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000356 AC: 52 AN: 1461654 Hom.: 0 Cov.: 31 AF XY: 0.0000413 AC XY: 30 AN XY: 727126

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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: 0.0000450

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152334 Hom.: 0 Cov.: 33 AF XY: 0.0000268 AC XY: 2 AN XY: 74492

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000588

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000151

ExAC AF: 0.0000247 AC: 3

EpiCase AF: 0.000109

EpiControl AF: 0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2C Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 08, 2022

This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 16 of the SGCG protein (p.Glu16Gln). This variant is present in population databases (rs546543109, gnomAD 0.005%). This variant has not been reported in the literature in individuals affected with SGCG-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glutamine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.076
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.41
Cadd	Benign	16
Dann	Uncertain	0.97
DEOGEN2	Benign	0.22	T
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.053
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Benign	0.69	T
M_CAP	Benign	0.0099	T
MetaRNN	Benign	0.099	T
MetaSVM	Benign	-0.39	T
MutationAssessor	Benign	1.3	L
MutationTaster	Benign	0.93	D;D;D
PrimateAI	Benign	0.32	T
PROVEAN	Benign	0.010	N
REVEL	Benign	0.14
Sift	Benign	0.28	T
Sift4G	Benign	0.60	T
Polyphen		0.0	B
Vest4		0.21
MutPred		0.31		Loss of catalytic residue at E16 (P = 0.1607);
MVP		0.83
MPC		0.067
ClinPred		0.061	T
GERP RS		4.5
Varity_R		0.095
gMVP		0.63

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

Other links and lift over

dbSNP: rs546543109; hg19: chr13-23777879; COSMIC: COSV105104624;