chr20-33408776-G-C

Variant names:

• chr20-33408776-G-C
• rs116747979
• NM_003098.3:c.1350C>G

Variant summary

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

The NM_003098.3(SNTA1):​c.1350C>G​(p.Phe450Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,852 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. F450F) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SNTA1 NM_003098.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.856
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• long QT syndrome 12

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• long QT syndrome

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000288878 (HGNC:):

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, 0.827

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003098.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	NM_003098.3	MANE Select	c.1350C>G	p.Phe450Leu	missense	Exon 7 of 8	NP_003089.1
	SNTA1	NM_001424413.1		c.1350C>G	p.Phe450Leu	missense	Exon 7 of 8	NP_001411342.1
	SNTA1	NM_001424414.1		c.1382C>G	p.Ser461Trp	missense	Exon 7 of 8	NP_001411343.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SNTA1	ENST00000217381.3	TSL:1 MANE Select	c.1350C>G	p.Phe450Leu	missense	Exon 7 of 8	ENSP00000217381.2
	ENSG00000288878	ENST00000785672.1		n.43-1277G>C		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461852 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727226

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

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: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111980

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Benign	0.011	T
BayesDel_noAF	Benign	-0.22
CADD	Benign	14
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D
Eigen	Benign	-0.44
Eigen_PC	Benign	-0.72
FATHMM_MKL	Benign	0.17	N
LIST_S2	Uncertain	0.96	D
M_CAP	Benign	0.080	D
MetaRNN	Pathogenic	0.83	D
MetaSVM	Uncertain	0.28	D
MutationAssessor	Uncertain	2.4	M
PhyloP100		-0.86
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-4.8	D
REVEL	Uncertain	0.56
Sift	Uncertain	0.0040	D
Sift4G	Uncertain	0.0070	D
Polyphen		1.0	D
Vest4		0.89
MutPred		0.60		Gain of disorder (P = 0.0767)
MVP		0.62
MPC		0.95
ClinPred		1.0	D
GERP RS		-9.0
Varity_R		0.50
gMVP		0.86
Mutation Taster		=33/67	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: rs116747979; hg19: chr20-31996582;