rs757481230

Positions:

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_000023.4(SGCA):c.614C>A(p.Pro205His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000558 in 1,613,852 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P205L) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SGCA
NM_000023.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:7U:1

Conservation

PhyloP100: 2.77

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 11 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, 5 uncertain in NM_000023.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr17-50169121-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 423721.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Uncertain_significance=1}.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.968

PP5

Variant 17-50169121-C-A is Pathogenic according to our data. Variant chr17-50169121-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 289794.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=5, Uncertain_significance=1, Pathogenic=2}. Variant chr17-50169121-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
SGCA	NM_000023.4 linkuse as main transcript	c.614C>A	p.Pro205His	missense_variant	6/10	ENST00000262018.8
SGCA	NM_001135697.3 linkuse as main transcript	c.584+549C>A		intron_variant
SGCA	NR_135553.2 linkuse as main transcript	n.650C>A		non_coding_transcript_exon_variant	6/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SGCA	ENST00000262018.8 linkuse as main transcript	c.614C>A	p.Pro205His	missense_variant	6/10	1	NM_000023.4	P1	Q16586-1

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251216

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135770

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461722

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727164

show subpopulations

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:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152130

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74312

show subpopulations

Gnomad4 AFR

AF:

0.000121

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000567

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:7Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2D

Pathogenic:3Uncertain:1

Likely pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 19, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Oct 30, 2017	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 08, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 16, 2024	This sequence change replaces proline, which is neutral and non-polar, with histidine, which is basic and polar, at codon 205 of the SGCA protein (p.Pro205His). This variant is present in population databases (rs757481230, gnomAD 0.007%). This missense change has been observed in individual(s) with limb-girdle muscular dystrophy (PMID: 9032047; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 289794). 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 with a positive predictive value of 95%. This variant disrupts the p.Pro205 amino acid residue in SGCA. Other variant(s) that disrupt this residue have been observed in individuals with SGCA-related conditions (PMID: 18996010), which suggests that this may be a clinically significant amino acid residue. For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Nov 15, 2019	The frequency of this variant in the general population is consistent with pathogenicity. Found in at least one patient with expected phenotype for this gene. Predicted to have a damaging effect on the protein. In multiple individuals, this variant has been seen with a single recessive pathogenic variant in the same gene, suggesting this variant may also be pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jun 26, 2017	A P205H variant that is likely pathogenic has been identified in the SGCA gene. The P205H variant has been reported previously in the compound heterozygous state in an individual with LGMD and complete alpha-sarcoglycan deficiency on immunoblot screening and in an individual with a DMD-like phenotype and partial alpha-sarcoglycan deficiency on immunoblot screening; however, functional characterization of the variant was not performed (Duggan et al., 1997). The P205H variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. Additionally, this substitution occurs at a position that is conserved in mammals, and missense variants at the same position (P205S) and in a nearby residue (T208I/A) have been reported in the Human Gene Mutation Database in association with LGMD (Stenson et al., 2014). In silico analysis predicts this variant is probably damaging to the protein structure/function. Furthermore, P205H was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Therefore, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jul 04, 2018	- -

Autosomal recessive limb-girdle muscular dystrophy

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jun 01, 2023

Variant summary: SGCA c.614C>A (p.Pro205His) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 251216 control chromosomes (gnomAD). c.614C>A has been reported in the literature in individuals affected with Limb-Girdle Muscular Dystrophy and hyperCKaemia (examples: Duggan_1997, Ganapathy_2019, Wong_2022). These data indicate that the variant is likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 9032047, 31069529, 35948506). Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as pathogenic/likely pathogenic (n=4) or VUS (n=2). Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.46

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.85

Eigen

Uncertain

0.56

Eigen_PC

Uncertain

0.53

FATHMM_MKL

Uncertain

0.81

LIST_S2

Benign

0.77

M_CAP

Pathogenic

0.30

MetaRNN

Pathogenic

0.97

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.5

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.68

PROVEAN

Uncertain

-3.1

REVEL

Pathogenic

0.84

Sift

Uncertain

0.012

Sift4G

Benign

0.061

Polyphen

1.0

Vest4

0.86

MutPred

0.85

Gain of catalytic residue at P205 (P = 0.0466);

MVP

1.0

MPC

1.2

ClinPred

0.95

GERP RS

5.1

Varity_R

0.26

gMVP

0.62

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over