rs148132791

Positions:

• chr17-50167485-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_000023.4(SGCA):​c.155T>G​(p.Val52Gly) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000774 in 1,614,054 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: 𝑓 0.000079 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000077 (0 hom.)
• Consequence: SGCA NM_000023.4 missense, splice_region
• Scores: Splicing: ADA: 0.0001179
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: -0.525

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM1: In a topological_domain Extracellular (size 266) in uniprot entity SGCA_HUMAN there are 108 pathogenic changes around while only 2 benign (98%) in NM_000023.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.07145178).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SGCA	NM_000023.4	c.155T>G	p.Val52Gly	missense_variant, splice_region_variant	2/10	ENST00000262018.8	NP_000014.1
SGCA	NM_001135697.3	c.155T>G	p.Val52Gly	missense_variant, splice_region_variant	2/8		NP_001129169.1
SGCA	NR_135553.2	n.191T>G		splice_region_variant, non_coding_transcript_exon_variant	2/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SGCA	ENST00000262018.8	c.155T>G	p.Val52Gly	missense_variant, splice_region_variant	2/10	1	NM_000023.4	ENSP00000262018.3

Frequencies

GnomAD3 genomes AF: 0.0000789 AC: 12 AN: 152184 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000121

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: 0.000103

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000358 AC: 9 AN: 251426 Hom.: 0 AF XY: 0.0000368 AC XY: 5 AN XY: 135904

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: 0.0000703

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000773 AC: 113 AN: 1461870 Hom.: 0 Cov.: 32 AF XY: 0.0000784 AC XY: 57 AN XY: 727240

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.000101

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000789 AC: 12 AN: 152184 Hom.: 0 Cov.: 32 AF XY: 0.0000538 AC XY: 4 AN XY: 74338

Gnomad4 AFR AF: 0.000121

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000103

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000132 Hom.: 0

Bravo AF: 0.0000642

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000412 AC: 5

EpiCase AF: 0.000109

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2D Uncertain:3

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 16, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 25, 2022	This sequence change replaces valine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 52 of the SGCA protein (p.Val52Gly). This variant is present in population databases (rs148132791, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with SGCA-related conditions. ClinVar contains an entry for this variant (Variation ID: 281286). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Feb 08, 2023	- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Jul 01, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.088
BayesDel_addAF	Benign	-0.12	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	2.3
DANN	Benign	0.89
DEOGEN2	Uncertain	0.61	.;D
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.033	N
LIST_S2	Benign	0.44	T;T
M_CAP	Uncertain	0.12	D
MetaRNN	Benign	0.071	T;T
MetaSVM	Uncertain	0.11	D
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-0.40	N;N
REVEL	Benign	0.26
Sift	Benign	0.14	T;T
Sift4G	Benign	0.21	T;T
Polyphen		0.0050	B;B
Vest4		0.15
MVP		0.65
MPC		0.44
ClinPred		0.011	T
GERP RS		-0.91
Varity_R		0.036
gMVP		0.78

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00012
dbscSNV1_RF	Benign	0.032
SpliceAI score (max)		0.010		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: rs148132791; hg19: chr17-48244846;