rs727503422

Positions:

• chr5-156508703-G-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1_Strong PM2 PP3_Strong PP5_Very_Strong

The NM_000337.6(SGCD):​c.294+1G>A variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SGCD NM_000337.6 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.46

Genes affected

SGCD (HGNC:10807): (sarcoglycan delta) The protein encoded by this gene is one of the four known components of the sarcoglycan complex, which is a subcomplex of the dystrophin-glycoprotein complex (DGC). DGC forms a link between the F-actin cytoskeleton and the extracellular matrix. This protein is expressed most abundantly in skeletal and cardiac muscle. Mutations in this gene have been associated with autosomal recessive limb-girdle muscular dystrophy and dilated cardiomyopathy. Alternatively spliced transcript variants encoding distinct isoforms have been observed for this gene. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.11569301 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 5-156508703-G-A is Pathogenic according to our data. Variant chr5-156508703-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 165232.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SGCD	NM_000337.6	c.294+1G>A		splice_donor_variant		ENST00000337851.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SGCD	ENST00000337851.9	c.294+1G>A		splice_donor_variant		1	NM_000337.6	P4
SGCD	ENST00000435422.7	c.291+1G>A		splice_donor_variant		1		A1
SGCD	ENST00000517913.5	c.294+1G>A		splice_donor_variant		5
SGCD	ENST00000524347.2	c.*158+1G>A		splice_donor_variant, NMD_transcript_variant		5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1389658 Hom.: 0 Cov.: 22 AF XY: 0.00 AC XY: 0 AN XY: 693786

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000371 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal recessive limb-girdle muscular dystrophy type 2F Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 02, 2024	This sequence change affects a donor splice site in intron 4 of the SGCD gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in SGCD are known to be pathogenic (PMID: 8841194, 10735275, 10838250). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SGCD-related conditions. ClinVar contains an entry for this variant (Variation ID: 165232). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Feb 08, 2023	- -

Neuromuscular disease Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Sep 29, 2014

The 294+1G>A variant in SGCD has not been previously reported in individuals wit h cardiomyopathy or myopathy and was absent from large population studies. This variant occurs in the invariant region (+/- 1,2) of the splice consensus sequenc e and is predicted to cause altered splicing leading to an abnormal or absent pr otein. Homozygous LOF variants in the SGCD gene have been reported in autosomal recessive Limb-Girdle muscular dystrophy (LGMD; OMIM, Human Gene Mutation Databa se). The clinical significance of a heterozygous LOF variant for DCM in the abse nce of muscular dystrophy is unknown. In summary, although additional studies ar e required to fully establish its clinical significance, the 294+1G>A variant is likely pathogenic for Limb-Girdle muscular dystrophy in an autosomal recessive manner. -

Autosomal recessive limb-girdle muscular dystrophy type 2F;C1847667:Dilated cardiomyopathy 1L Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Counsyl

Mar 19, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.41
CADD	Pathogenic	33
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		5.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DL_spliceai		1.0		Position offset: -1

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs727503422; hg19: chr5-155935713;