chr19-35033664-C-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1PM2PP3_Strong

The NM_001037.5(SCN1B):c.373C>T(p.Arg125Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000186 in 1,614,064 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SCN1B
NM_001037.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:5U:1B:1

Conservation

PhyloP100: 5.66

Variant links:

Genes affected

SCN1B (HGNC:10586): (sodium voltage-gated channel beta subunit 1) Voltage-gated sodium channels are heteromeric proteins that function in the generation and propagation of action potentials in muscle and neuronal cells. They are composed of one alpha and two beta subunits, where the alpha subunit provides channel activity and the beta-1 subunit modulates the kinetics of channel inactivation. This gene encodes a sodium channel beta-1 subunit. Mutations in this gene result in generalized epilepsy with febrile seizures plus, Brugada syndrome 5, and defects in cardiac conduction. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Oct 2009]

SCN1B links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

PM1

In a domain Ig-like C2-type (size 128) in uniprot entity SCN1B_HUMAN there are 7 pathogenic changes around while only 3 benign (70%) in NM_001037.5

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.985

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN1B	NM_001037.5 link	c.373C>T	p.Arg125Cys	missense_variant	Exon 3 of 6	ENST00000262631.11	NP_001028.1	Q07699-1
SCN1B	NM_199037.5 link	c.373C>T	p.Arg125Cys	missense_variant	Exon 3 of 3		NP_950238.1	Q07699-2
SCN1B	NM_001321605.2 link	c.274C>T	p.Arg92Cys	missense_variant	Exon 3 of 6		NP_001308534.1	Q07699A0A1W2PR05

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN1B	ENST00000262631.11 link	c.373C>T	p.Arg125Cys	missense_variant	Exon 3 of 6	1	NM_001037.5	ENSP00000262631.3		Q07699-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152170

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152170

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74326

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:5Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Pathogenic:2

Jan 15, 2025

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Published functional studies demonstrate decreased cell surface expression and decreased sodium current density in the homozygous state (PMID: 19710327); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Appeared to segregate with epilepsy in the heterozygous state in several members of a family previously tested at GeneDx, and also identified in the heterozygous state in unrelated individuals with febrile, focal, and generalized seizures tested at GeneDx; This variant is associated with the following publications: (PMID: 27586289, 23934645, 26042039, 29307654, 24737232, 21040232, 23148524, 21463283, 28681755, 28927993, 28965169, 20375142, 23182416, 36291443, Pugliese2023[article], 35359639, 19710327) -

Nov 20, 2023

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Developmental and epileptic encephalopathy, 52

Pathogenic:2

Oct 09, 2020

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Feb 28, 2023

Institute of Immunology and Genetics Kaiserslautern

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ACMG Criteria: PS3, PM2, PM5, PP3, PP5; Variant was found in homozygous state. -

Generalized epilepsy with febrile seizures plus, type 1;C2748541:Brugada syndrome 5;C3809311:Atrial fibrillation, familial, 13;C4479236:Developmental and epileptic encephalopathy, 52

Pathogenic:1

Oct 07, 2022

Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been reported in the literature in the homozygous state in two individuals with epilepsy and other features suggestive of Dravet syndrome (Patino 2009 PMID: 19710327; Mukherjee 2017 PMID: 28681755). It has also been identified in the heterozygous state in two unrelated individuals with epilepsy at an external laboratory, segregating with disease in similarly affected family members in one family (GeneDx; ClinVar Variation ID: 375686); personal communication). This variant is present in the Genome Aggregation Database (Highest reported MAF: 0.007% [1/15280]; https://gnomad.broadinstitute.org/variant/19-35033664-C-T?dataset=gnomad_r3), and in ClinVar, with classifications ranging from likely pathogenic to likely benign (Variation ID: 375686). In vitro functional studies suggest that this variant impacts sodium channel activity and cell surface protein expression (Patino 2009 PMID: 19710327); however, these studies may not accurately represent in vivo biological function. Evolutionary conservation and computational predictive tools support that this variant may impact the protein. In summary, data on this variant is highly suspicious for disease, but requires further evidence for pathogenicity. Therefore, this variant is classified as likely pathogenic. -

Brugada syndrome 5

Uncertain:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 125 of the SCN1B protein (p.Arg125Cys). This variant is present in population databases (no rsID available, gnomAD 0.1%). This missense change has been observed in individuals with autosomal recessive SCN1B-related conditions (PMID: 19710327, 28681755). ClinVar contains an entry for this variant (Variation ID: 375686). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects SCN1B function (PMID: 19710327). This variant disrupts the p.Arg125 amino acid residue in SCN1B. Other variant(s) that disrupt this residue have been observed in individuals with SCN1B-related conditions (internal data), which suggests that this may be a clinically significant amino acid residue. 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. -

Seizure

Benign:1

Nov 25, 2021

Génétique des Maladies du Développement, Hospices Civils de Lyon

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

inherited from healthy carrier -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

1.0

BayesDel_addAF

Pathogenic

0.53

BayesDel_noAF

Pathogenic

0.52

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.63

D;D;.;.;.

Eigen

Uncertain

0.62

Eigen_PC

Uncertain

0.57

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.93

.;D;D;D;D

M_CAP

Pathogenic

0.52

MetaRNN

Pathogenic

0.98

D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Uncertain

2.1

M;M;M;.;.

PrimateAI

Uncertain

0.76

PROVEAN

Pathogenic

-6.1

D;.;D;.;.

REVEL

Pathogenic

0.92

Sift

Pathogenic

0.0

D;.;D;.;.

Sift4G

Uncertain

0.0020

D;.;D;.;.

Polyphen

1.0

D;D;D;.;.

Vest4

0.90

MutPred

0.91

Gain of catalytic residue at L126 (P = 0.0107);Gain of catalytic residue at L126 (P = 0.0107);Gain of catalytic residue at L126 (P = 0.0107);.;.;

MVP

0.99

MPC

2.0

ClinPred

1.0

GERP RS

4.2

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.84

gMVP

0.96

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