rs1553940073

Variant names:

• chr4-52028014-C-T
• rs1553940073
• NM_000232.5:c.707G>A

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_000232.5(SGCB):​c.707G>A​(p.Gly236Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,294 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. G236G) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SGCB NM_000232.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.78
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.924

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCB	NM_000232.5	c.707G>A	p.Gly236Asp	missense_variant	Exon 5 of 6	ENST00000381431.10	NP_000223.1
SGCB	NM_001440519.1	c.497G>A	p.Gly166Asp	missense_variant	Exon 4 of 5		NP_001427448.1
SGCB	NM_001440520.1	c.410G>A	p.Gly137Asp	missense_variant	Exon 6 of 7		NP_001427449.1
SGCB	XM_047416076.1	c.410G>A	p.Gly137Asp	missense_variant	Exon 4 of 5		XP_047272032.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCB	ENST00000381431.10	c.707G>A	p.Gly236Asp	missense_variant	Exon 5 of 6	1	NM_000232.5	ENSP00000370839.6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461294 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 726990

African (AFR) AF: 0.00 AC: 0 AN: 33462

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39644

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111548

Other (OTH) AF: 0.00 AC: 0 AN: 60368

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2E Uncertain:1

Sep 13, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a SGCB-related disease. This sequence change replaces glycine with aspartic acid at codon 236 of the SGCB protein (p.Gly236Asp). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and aspartic acid. 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 disruptive, but these predictions have not been confirmed by published functional studies. In summary, this variant is a novel missense change with uncertain impact on protein function. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.53	D
BayesDel_noAF	Pathogenic	0.52
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.96	D
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.92	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.5	M
PhyloP100		7.8
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.4	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.0050	D
Polyphen		1.0	D
Vest4		0.98
MutPred		0.69		Loss of MoRF binding (P = 0.0789);
MVP		0.99
MPC		0.44
ClinPred		0.99	D
GERP RS		5.3
Varity_R		0.81
gMVP		0.91
Mutation Taster		=22/78	disease causing

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

Other links and lift over

dbSNP: rs1553940073; hg19: chr4-52894180;