13-23203751-G-T

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.57G>T(p.Glu19Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,754 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. E19E) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: SGCG NM_000231.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 2.57

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=0.22884306).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SGCG	NM_000231.3	c.57G>T	p.Glu19Asp	missense_variant	2/8	ENST00000218867.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SGCG	ENST00000218867.4	c.57G>T	p.Glu19Asp	missense_variant	2/8	1	NM_000231.3	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251168 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135772

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000272

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461754 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727186

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000101

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.0000113

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

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

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 31, 2022	This sequence change replaces glutamic acid, which is acidic and polar, with aspartic acid, which is acidic and polar, at codon 19 of the SGCG protein (p.Glu19Asp). This variant is present in population databases (rs752669226, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with SGCG-related conditions. ClinVar contains an entry for this variant (Variation ID: 862021). 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 aspartic acid 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. -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 17, 2020	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.099
BayesDel_addAF	Benign	-0.23	T
BayesDel_noAF	Benign	-0.26
Cadd	Benign	17
Dann	Uncertain	1.0
DEOGEN2	Benign	0.35	T
Eigen	Benign	0.10
Eigen_PC	Benign	0.17
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Benign	0.71	T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.23	T
MetaSVM	Uncertain	0.063	D
MutationAssessor	Uncertain	2.4	M
MutationTaster	Benign	0.81	D;D;D
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-0.96	N
REVEL	Benign	0.28
Sift	Benign	0.076	T
Sift4G	Benign	0.32	T
Polyphen		0.50	P
Vest4		0.20
MutPred		0.30		Gain of MoRF binding (P = 0.2824);
MVP		0.89
MPC		0.13
ClinPred		0.35	T
GERP RS		4.6
Varity_R		0.13
gMVP		0.54

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

Other links and lift over

dbSNP: rs752669226; hg19: chr13-23777890; COSMIC: COSV54557580;