chr20-33408776-G-A

Position:

chr20-33408776-G-A

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_001424414.1(SNTA1):c.1382C>T(p.Ser461Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00207 in 1,614,120 control chromosomes in the GnomAD database, including 59 homozygotes. In-silico tool predicts a benign outcome for this variant. 5/6 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.011 ( 34 hom., cov: 32)

Exomes 𝑓: 0.0011 ( 25 hom. )

Consequence

SNTA1
NM_001424414.1 missense

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:8

Conservation

PhyloP100: -0.856

Variant links:

Genes affected

SNTA1 (HGNC:11167): (syntrophin alpha 1) Syntrophins are cytoplasmic peripheral membrane scaffold proteins that are components of the dystrophin-associated protein complex. This gene is a member of the syntrophin gene family and encodes the most common syntrophin isoform found in cardiac tissues. The N-terminal PDZ domain of this syntrophin protein interacts with the C-terminus of the pore-forming alpha subunit (SCN5A) of the cardiac sodium channel Nav1.5. This protein also associates cardiac sodium channels with the nitric oxide synthase-PMCA4b (plasma membrane Ca-ATPase subtype 4b) complex in cardiomyocytes. This gene is a susceptibility locus for Long-QT syndrome (LQT) - an inherited disorder associated with sudden cardiac death from arrhythmia - and sudden infant death syndrome (SIDS). This protein also associates with dystrophin and dystrophin-related proteins at the neuromuscular junction and alters intracellular calcium ion levels in muscle tissue. [provided by RefSeq, Jan 2013]

SNTA1 links:

LOC124904889 (HGNC:):

LOC124904889 links:

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ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -20 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.68).

BP6

Variant 20-33408776-G-A is Benign according to our data. Variant chr20-33408776-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 239498.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr20-33408776-G-A is described in Lovd as [Benign].

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0112 (1703/152268) while in subpopulation AFR AF= 0.0385 (1601/41550). AF 95% confidence interval is 0.037. There are 34 homozygotes in gnomad4. There are 784 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

BS2

High AC in GnomAd4 at 1703 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNTA1	NM_003098.3 linkuse as main transcript	c.1350C>T	p.Phe450Phe	synonymous_variant	7/8	ENST00000217381.3	NP_003089.1	Q13424-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNTA1	ENST00000217381.3 linkuse as main transcript	c.1350C>T	p.Phe450Phe	synonymous_variant	7/8	1	NM_003098.3	ENSP00000217381.2		Q13424-1

Frequencies

GnomAD3 genomes

AF:

0.0112

AC:

1702

AN:

152150

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0386

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00386

Gnomad ASJ

AF:

0.00288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000206

Gnomad OTH

AF:

0.00860

GnomAD3 exomes

AF:

0.00288

AC:

724

AN:

251430

Hom.:

AF XY:

0.00213

AC XY:

289

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.0386

Gnomad AMR exome

AF:

0.00147

Gnomad ASJ exome

AF:

0.00198

Gnomad EAS exome

AF:

0.000163

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000967

Gnomad OTH exome

AF:

0.00163

GnomAD4 exome

AF:

0.00112

AC:

1637

AN:

1461852

Hom.:

Cov.:

AF XY:

0.00100

AC XY:

729

AN XY:

727226

show subpopulations

Gnomad4 AFR exome

AF:

0.0385

Gnomad4 AMR exome

AF:

0.00179

Gnomad4 ASJ exome

AF:

0.00184

Gnomad4 EAS exome

AF:

0.0000756

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000495

Gnomad4 OTH exome

AF:

0.00240

GnomAD4 genome

AF:

0.0112

AC:

1703

AN:

152268

Hom.:

Cov.:

AF XY:

0.0105

AC XY:

784

AN XY:

74460

show subpopulations

Gnomad4 AFR

AF:

0.0385

Gnomad4 AMR

AF:

0.00386

Gnomad4 ASJ

AF:

0.00288

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000206

Gnomad4 OTH

AF:

0.00851

Alfa

AF:

0.00583

Hom.:

Bravo

AF:

0.0121

Asia WGS

AF:

0.00115

AC:

AN:

3478

EpiCase

AF:

0.000164

EpiControl

AF:

0.000178

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Long QT syndrome 12

Benign:2

Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Sep 21, 2023	- -

not provided

Benign:2

Likely benign, criteria provided, single submitter	not provided	Breakthrough Genomics, Breakthrough Genomics	-	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 03, 2015	- -

not specified

Benign:1

Benign, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Sep 17, 2018

Variant summary: SNTA1 c.1350C>T alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.0035 in 277164 control chromosomes, predominantly at a frequency of 0.036 within the African subpopulation in the gnomAD database, including 16 homozygotes. The observed variant frequency within African control individuals in the gnomAD database is approximately 3600-fold of the estimated maximal expected allele frequency for a pathogenic variant in SNTA1 causing Arrhythmia phenotype (1e-05), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African origin. To our knowledge, no occurrence of c.1350C>T in individuals affected with Arrhythmia and no experimental evidence demonstrating its impact on protein function have been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -

Congenital long QT syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jun 14, 2016

- -

Long QT syndrome

Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 29, 2024

- -

Cardiovascular phenotype

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 02, 2015

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.68

CADD

Benign

3.1

DANN

Benign

0.68

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over