20-33412677-A-G

Position:

• chr20-33412677-A-G

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BA1

The NM_003098.3(SNTA1):​c.807T>C​(p.Asn269Asn) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00392 in 1,613,822 control chromosomes in the GnomAD database, including 205 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.020 (103 hom., cov: 32)
  • Exomes 𝑓: 0.0022 (102 hom.)
• Consequence: SNTA1 NM_003098.3 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:9
• Conservation: PhyloP100: -0.222

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]

LOC124904889 (HGNC:):

ACMG classification

Verdict is Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.93).
• BP6: Variant 20-33412677-A-G is Benign according to our data. Variant chr20-33412677-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 263424.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr20-33412677-A-G is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=-0.222 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (AFR) allele frequency at 95% confidence interval = 0.0675 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNTA1	NM_003098.3	c.807T>C	p.Asn269Asn	synonymous_variant	4/8	ENST00000217381.3	NP_003089.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNTA1	ENST00000217381.3	c.807T>C	p.Asn269Asn	synonymous_variant	4/8	1	NM_003098.3	ENSP00000217381.2

Frequencies

GnomAD3 genomes AF: 0.0203 AC: 3087 AN: 152094 Hom.: 101 Cov.: 32

Gnomad AFR AF: 0.0693

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0107

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000208

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00633

Gnomad NFE AF: 0.000176

Gnomad OTH AF: 0.0172

GnomAD3 exomes AF: 0.00499 AC: 1252 AN: 251044 Hom.: 36 AF XY: 0.00362 AC XY: 492 AN XY: 135812

Gnomad AFR exome AF: 0.0678

Gnomad AMR exome AF: 0.00321

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000981

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000159

Gnomad OTH exome AF: 0.00326

GnomAD4 exome AF: 0.00221 AC: 3223 AN: 1461610 Hom.: 102 Cov.: 33 AF XY: 0.00192 AC XY: 1397 AN XY: 727122

Gnomad4 AFR exome AF: 0.0762

Gnomad4 AMR exome AF: 0.00367

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000812

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000953

Gnomad4 OTH exome AF: 0.00604

GnomAD4 genome AF: 0.0204 AC: 3106 AN: 152212 Hom.: 103 Cov.: 32 AF XY: 0.0202 AC XY: 1502 AN XY: 74420

Gnomad4 AFR AF: 0.0696

Gnomad4 AMR AF: 0.0107

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000208

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000176

Gnomad4 OTH AF: 0.0170

Alfa AF: 0.00788 Hom.: 19

Bravo AF: 0.0230

Asia WGS AF: 0.00664 AC: 24 AN: 3478

EpiCase AF: 0.000164

EpiControl AF: 0.0000593

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:9

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:2

Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -

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	Jul 10, 2021	- -

not provided Benign:2

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

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 31, 2024

- -

Cardiovascular phenotype Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 10, 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	-0.93
CADD	Benign	0.49
DANN	Benign	0.27

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

Other links and lift over

dbSNP: rs73270015; hg19: chr20-32000483;