NM_000337.6:c.744T>G

Variant names:

• chr5-156759261-T-G
• rs1160680799
• NM_000337.6:c.744T>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000337.6(SGCD):​c.744T>G​(p.His248Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,544 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: SGCD NM_000337.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.965
• Publications: 0 publications found

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]

SGCD 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 2F

  Inheritance: AR Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Myriad Women’s Health, Ambry Genetics
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• dilated cardiomyopathy 1L

  Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.01647228).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCD	NM_000337.6	c.744T>G	p.His248Gln	missense_variant	Exon 9 of 9	ENST00000337851.9	NP_000328.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCD	ENST00000337851.9	c.744T>G	p.His248Gln	missense_variant	Exon 9 of 9	1	NM_000337.6	ENSP00000338343.4
SGCD	ENST00000435422.7	c.741T>G	p.His247Gln	missense_variant	Exon 8 of 8	1		ENSP00000403003.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461544 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727054

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33474

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53400

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

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111742

Other (OTH) AF: 0.00 AC: 0 AN: 60362

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.029673), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

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

Mar 26, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces histidine with glutamine at codon 248 of the SGCD protein (p.His248Gln). The histidine residue is weakly conserved and there is a small physicochemical difference between histidine and glutamine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a SGCD-related disease. 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, but these predictions have not been confirmed by published functional studies. In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.059
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.44
CADD	Benign	0.020
DANN	Benign	0.77
DEOGEN2	Uncertain	0.47	T;.
Eigen	Benign	-2.0
Eigen_PC	Benign	-1.9
FATHMM_MKL	Benign	0.042	N
LIST_S2	Benign	0.48	T;T
M_CAP	Benign	0.026	D
MetaRNN	Benign	0.016	T;T
MetaSVM	Benign	-0.68	T
MutationAssessor	Benign	-1.3	N;.
PhyloP100		-0.96
PrimateAI	Benign	0.29	T
PROVEAN	Benign	0.98	N;N
REVEL	Benign	0.24
Sift	Benign	0.62	T;T
Sift4G	Benign	0.62	T;T
Polyphen		0.0	B;B
Vest4		0.033
MutPred		0.29		Loss of catalytic residue at H247 (P = 0.0394);.;
MVP		0.40
MPC		0.12
ClinPred		0.057	T
GERP RS		-9.9
Varity_R		0.041
gMVP		0.24
Mutation Taster		=78/22	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.050		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: rs1160680799; hg19: chr5-156186272;