dbSNP rs751466815: SGCA:c.37+6T>C (chr17-50166083-T-C) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3

The NM_000023.4(SGCA):c.37+6T>C variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,612,594 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

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

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

SGCA
NM_000023.4 splice_region, intron

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:6

Conservation

PhyloP100: 0.306

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:

LOC105371818 (HGNC:):

LOC105371818 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCA	NM_000023.4 link	c.37+6T>C		splice_region_variant, intron_variant	Intron 1 of 9	ENST00000262018.8	NP_000014.1	Q16586-1A0A0S2Z4Q1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCA	ENST00000262018.8 link	c.37+6T>C		splice_region_variant, intron_variant	Intron 1 of 9	1	NM_000023.4	ENSP00000262018.3		Q16586-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152116

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:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000401

AC:

AN:

249078

Hom.:

AF XY:

0.00000742

AC XY:

AN XY:

134810

show subpopulations

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:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1460478

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726664

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152116

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74306

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:6

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2D

Pathogenic:1Uncertain:4

Jun 22, 2023

Neuberg Centre For Genomic Medicine, NCGM

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The splice region c.37+6T>C variant in SGCA gene has not been reported previously as a pathogenic variant nor as a benign variant, to our knowledge. The c.37+6T>C variant is present with allele frequency of 0.0007% in gnomAD Exomes. This variant has been submitted to the ClinVar database as Uncertain Significance. SpliceAI predicts this variant to cause splice donor loss (score-0.51). For these reasons, this variant has been classified as Variant of Uncertain Significance (VUS). -

Sep 16, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 01, 2022

Revvity Omics, Revvity

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 05, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 1 of the SGCA gene. It does not directly change the encoded amino acid sequence of the SGCA protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs751466815, gnomAD 0.003%). This variant has been observed in individuals with clinical features of limb-girdle muscular dystrophy (PMID: 35116532; internal data). ClinVar contains an entry for this variant (Variation ID: 281148). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant alters mRNA splicing and is expected to lead to the loss of protein expression (external communication). For these reasons, this variant has been classified as Pathogenic. -

Feb 08, 2023

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

SGCA-related disorder

Uncertain:1

Jan 05, 2024

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The SGCA c.37+6T>C variant is predicted to interfere with splicing. This variant was reported in the homozygous state in two individuals with sarcoglycanopathy (Bardhan et al 2022. PubMed ID: 35416532). At PreventionGenetics, we have observed this variant with a second SGCA variant in a patient tested for metabolic myopathy (internal data). This variant is reported in 0.0033% of alleles in individuals of South Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/17-48243444-T-C). Although we suspect this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

not provided

Uncertain:1

Jun 19, 2016

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.60

CADD

Benign

DANN

Benign

0.55

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.51

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.51

Position offset: -6

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