17-50167418-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1PM2PP3_ModeratePP5_Moderate

The NM_000023.4(SGCA):c.88C>T(p.Pro30Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,866 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P30L) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SGCA
NM_000023.4 missense

Scores

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 2.47

Publications

2 publications found

Variant links:

Genes affected

SGCA (HGNC:10805): (sarcoglycan alpha) This gene encodes a component of the dystrophin-glycoprotein complex (DGC), which is critical to the stability of muscle fiber membranes and to the linking of the actin cytoskeleton to the extracellular matrix. Its expression is thought to be restricted to striated muscle. Mutations in this gene result in type 2D autosomal recessive limb-girdle muscular dystrophy. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008]

SGCA 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 2D
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Myriad Women’s Health, Laboratory for Molecular Medicine, Orphanet

SGCA links:

ENSG00000253730 (HGNC:):

ENSG00000253730 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM1

In a hotspot region, there are 7 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 5 uncertain in NM_000023.4

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.893

PP5

Variant 17-50167418-C-T is Pathogenic according to our data. Variant chr17-50167418-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 471339.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
SGCA	NM_000023.4 link	c.88C>T	p.Pro30Ser	missense_variant	Exon 2 of 10	ENST00000262018.8	NP_000014.1
SGCA	NM_001135697.3 link	c.88C>T	p.Pro30Ser	missense_variant	Exon 2 of 8		NP_001129169.1
SGCA	NR_135553.2 link	n.124C>T		non_coding_transcript_exon_variant	Exon 2 of 9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCA	ENST00000262018.8 link	c.88C>T	p.Pro30Ser	missense_variant	Exon 2 of 10	1	NM_000023.4	ENSP00000262018.3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251436

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS 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:

6.84e-7

AC:

AN:

1461866

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727240

show subpopulations

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

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111992

Other (OTH)

AF:

0.00

AC:

AN:

60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.275

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2D

Pathogenic:1

Dec 02, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense change has been observed in individual(s) with clinical suspicion of limb-girdle muscular dystrophy (Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt SGCA protein function. ClinVar contains an entry for this variant (Variation ID: 471339). This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 30 of the SGCA protein (p.Pro30Ser).

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.32

BayesDel_addAF

Uncertain

0.056

BayesDel_noAF

Uncertain

-0.080

CADD

Benign

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.0

.;D

Eigen

Benign

-0.12

Eigen_PC

Benign

-0.22

FATHMM_MKL

Benign

0.30

LIST_S2

Benign

0.81

T;T

M_CAP

Pathogenic

0.32

MetaRNN

Pathogenic

0.89

D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.4

M;M

PhyloP100

2.5

PrimateAI

Benign

0.40

PROVEAN

Benign

-0.93

N;N

REVEL

Uncertain

0.42

Sift

Uncertain

0.015

D;D

Sift4G

Uncertain

0.044

D;D

Vest4

0.49

ClinPred

0.93

GERP RS

4.5

Varity_R

0.062

gMVP

0.75

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.12

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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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over