rs754465904

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1PM2PP2BP4

The NM_000232.5(SGCB):c.502A>G(p.Met168Val) variant causes a missense change. The variant allele was found at a frequency of 0.0000316 in 1,613,706 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. M168I) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

SGCB
NM_000232.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 4.12

Publications

0 publications found

Variant links:

Genes affected

SGCB (HGNC:10806): (sarcoglycan beta) This gene encodes a member of the sarcoglycan family. Sarcoglycans are transmembrane components in the dystrophin-glycoprotein complex which help stabilize the muscle fiber membranes and link the muscle cytoskeleton to the extracellular matrix. Mutations in this gene have been associated with limb-girdle muscular dystrophy.[provided by RefSeq, Oct 2008]

SGCB Gene-Disease associations (from GenCC):

autosomal recessive limb-girdle muscular dystrophy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
autosomal recessive limb-girdle muscular dystrophy type 2E
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), Orphanet

SGCB links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_000232.5

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 0 curated benign missense variants. Gene score misZ: -0.0049736 (below the threshold of 3.09). Trascript score misZ: -0.4279 (below the threshold of 3.09). GenCC associations: The gene is linked to autosomal recessive limb-girdle muscular dystrophy type 2E, autosomal recessive limb-girdle muscular dystrophy.

BP4

Computational evidence support a benign effect (MetaRNN=0.28641433).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCB	NM_000232.5 link	c.502A>G	p.Met168Val	missense_variant	Exon 4 of 6	ENST00000381431.10	NP_000223.1	Q16585-1Q5U0N0
SGCB	NM_001440519.1 link	c.292A>G	p.Met98Val	missense_variant	Exon 3 of 5		NP_001427448.1
SGCB	NM_001440520.1 link	c.205A>G	p.Met69Val	missense_variant	Exon 5 of 7		NP_001427449.1
SGCB	XM_047416076.1 link	c.205A>G	p.Met69Val	missense_variant	Exon 3 of 5		XP_047272032.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCB	ENST00000381431.10 link	c.502A>G	p.Met168Val	missense_variant	Exon 4 of 6	1	NM_000232.5	ENSP00000370839.6		Q16585-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000398

AC:

AN:

251448

AF XY:

0.0000589

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000352

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000342

AC:

AN:

1461534

Hom.:

Cov.:

AF XY:

0.0000454

AC XY:

AN XY:

727098

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.0000894

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39680

South Asian (SAS)

AF:

0.0000928

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000324

AC:

AN:

1111726

Other (OTH)

AF:

0.0000166

AC:

AN:

60386

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.470

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74342

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000412

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2E

Uncertain:3

Jul 12, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 168 of the SGCB protein (p.Met168Val). This variant is present in population databases (rs754465904, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with SGCB-related conditions. ClinVar contains an entry for this variant (Variation ID: 285160). 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 valine 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. -

Jul 28, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Oct 02, 2023

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:2

Jul 19, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 14, 2019

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 30564623) -

Qualitative or quantitative defects of beta-sarcoglycan

Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.086

BayesDel_addAF

Benign

-0.12

BayesDel_noAF

Benign

-0.18

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Uncertain

0.64

Eigen

Benign

-0.26

Eigen_PC

Benign

-0.13

FATHMM_MKL

Uncertain

0.94

LIST_S2

Benign

0.78

M_CAP

Uncertain

0.099

MetaRNN

Benign

0.29

MetaSVM

Uncertain

0.093

MutationAssessor

Benign

1.6

PhyloP100

4.1

PrimateAI

Benign

0.48

PROVEAN

Benign

-0.42

REVEL

Benign

0.28

Sift

Benign

0.095

Sift4G

Benign

0.11

Polyphen

0.026

Vest4

0.29

MutPred

0.30

Gain of catalytic residue at M168 (P = 0.0666);

MVP

0.96

MPC

0.069

ClinPred

0.077

GERP RS

4.2

Varity_R

0.23

gMVP

0.47

Mutation Taster

=83/17

polymorphism

(source)

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

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rs754465904

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over