4-52028063-CTT-C

Variant names:

• chr4-52028063-CTT-C
• rs775458201
• NM_000232.5:c.656_657delAA

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000232.5(SGCB):​c.656_657delAA​(p.Lys219SerfsTer2) variant causes a frameshift change. The variant allele was found at a frequency of 0.0000062 in 1,613,288 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: SGCB NM_000232.5 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 5.02

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]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.315 CDS is truncated, and there are 2 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-52028063-CTT-C is Pathogenic according to our data. Variant chr4-52028063-CTT-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 466603.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCB	NM_000232.5	c.656_657delAA	p.Lys219SerfsTer2	frameshift_variant	Exon 5 of 6	ENST00000381431.10	NP_000223.1
SGCB	XM_047416074.1	c.446_447delAA	p.Lys149SerfsTer2	frameshift_variant	Exon 4 of 5		XP_047272030.1
SGCB	XM_047416075.1	c.359_360delAA	p.Lys120SerfsTer2	frameshift_variant	Exon 4 of 5		XP_047272031.1
SGCB	XM_047416076.1	c.359_360delAA	p.Lys120SerfsTer2	frameshift_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.656_657delAA	p.Lys219SerfsTer2	frameshift_variant	Exon 5 of 6	1	NM_000232.5	ENSP00000370839.6

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152156 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000145

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461132 Hom.: 0 AF XY: 0.00000413 AC XY: 3 AN XY: 726946

Gnomad4 AFR exome AF: 0.000120

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152156 Hom.: 0 Cov.: 33 AF XY: 0.0000403 AC XY: 3 AN XY: 74352

Gnomad4 AFR AF: 0.000145

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: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000453

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2E Pathogenic:5

Jun 05, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 14, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys219Serfs*2) in the SGCB gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SGCB are known to be pathogenic (PMID: 15938573, 18285821). This variant is present in population databases (no rsID available, gnomAD 0.05%). This variant has not been reported in the literature in individuals affected with SGCB-related conditions. ClinVar contains an entry for this variant (Variation ID: 466603). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Apr 06, 2017

Counsyl

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jul 11, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 30, 2024

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs775458201; hg19: chr4-52894229;