7-94623379-G-T

Variant names:

• chr7-94623379-G-T
• rs557861177
• NM_003919.3:c.409C>A

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP3

The NM_003919.3(SGCE):​c.409C>A​(p.Arg137Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000069 in 1,450,158 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R137H) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: SGCE NM_003919.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.54
• Publications: 0 publications found

Genes affected

SGCE (HGNC:10808): (sarcoglycan epsilon) This gene encodes the epsilon member of the sarcoglycan family. Sarcoglycans are transmembrane proteins that are components of the dystrophin-glycoprotein complex, which link the actin cytoskeleton to the extracellular matrix. Unlike other family members which are predominantly expressed in striated muscle, the epsilon sarcoglycan is more broadly expressed. Mutations in this gene are associated with myoclonus-dystonia syndrome. This gene is imprinted, with preferential expression from the paternal allele. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. A pseudogene associated with this gene is located on chromosome 2. [provided by RefSeq, Oct 2016]

CASD1 (HGNC:16014): (CAS1 domain containing 1) Enables N-acetylneuraminate 7-O(or 9-O)-acetyltransferase activity. Involved in carbohydrate metabolic process. Is integral component of Golgi membrane. [provided by Alliance of Genome Resources, Apr 2022]

ACMG classification

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.838

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SGCE	NM_003919.3	c.409C>A	p.Arg137Ser	missense_variant	Exon 4 of 11	ENST00000648936.2	NP_003910.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SGCE	ENST00000648936.2	c.409C>A	p.Arg137Ser	missense_variant	Exon 4 of 11		NM_003919.3	ENSP00000497130.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.90e-7 AC: 1 AN: 1450158 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 721988

⚠️ 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: 33166

American (AMR) AF: 0.00 AC: 0 AN: 44542

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26002

East Asian (EAS) AF: 0.00 AC: 0 AN: 39468

South Asian (SAS) AF: 0.00 AC: 0 AN: 85442

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53274

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5692

European-Non Finnish (NFE) AF: 9.07e-7 AC: 1 AN: 1102640

Other (OTH) AF: 0.00 AC: 0 AN: 59932

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), 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

Myoclonic dystonia 11 Uncertain:1

Dec 14, 2022

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 (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of SGCE-related conditions (Invitae). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 854028). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt SGCE protein function. 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. This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 137 of the SGCE protein (p.Arg137Ser).

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.47	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.0	.;D;D;.;D;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;D;.;.;.
Eigen	Uncertain	0.57
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D;D;.;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D;.;D;D;D;D;D;D;D;D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.84	D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Benign	0.0	.;.;M;.;M;.;M;M;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.
PhyloP100		7.5
PrimateAI	Pathogenic	0.79	T
PROVEAN	Benign	0.0	.;N;.;.;N;.;.;N;N;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;N;.;.;N;.;.;.
REVEL	Benign	0.0
Sift	Pathogenic	0.0	.;T;.;.;T;.;.;D;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;T;.;.;.
Sift4G	Pathogenic	0.0	.;T;.;.;T;.;.;T;T;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;.;T;.;.;T;.;.;.
Vest4		0.0
ClinPred		0.96	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.36
gMVP		0.76
Mutation Taster		=31/69	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: rs557861177; hg19: chr7-94252691;