rs757554677

Variant names:

Variant summary

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

The NM_001037.5(SCN1B):c.133C>T(p.Arg45Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000372 in 1,614,026 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R45H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

SCN1B
NM_001037.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 3.26

Publications

4 publications found

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:

HPN-AS1 (HGNC:47041): (HPN antisense RNA 1)

HPN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
SCN1B	NM_001037.5 link	c.133C>T	p.Arg45Cys	missense_variant	Exon 2 of 6	ENST00000262631.11	NP_001028.1
SCN1B	NM_199037.5 link	c.133C>T	p.Arg45Cys	missense_variant	Exon 2 of 3		NP_950238.1
SCN1B	NM_001321605.2 link	c.34C>T	p.Arg12Cys	missense_variant	Exon 2 of 6		NP_001308534.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN1B	ENST00000262631.11 link	c.133C>T	p.Arg45Cys	missense_variant	Exon 2 of 6	1	NM_001037.5	ENSP00000262631.3

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152220

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:

0.000192

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

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251384

AF XY:

0.0000147

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461806

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727210

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53344

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1112004

Other (OTH)

AF:

0.00

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152220

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74362

show subpopulations

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

41446

American (AMR)

AF:

0.0000654

AC:

AN:

15284

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000192

AC:

AN:

5204

South Asian (SAS)

AF:

0.00

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2092

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.0296732), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Aug 25, 2016

Genetic Services Laboratory, University of Chicago

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Brugada syndrome 5

Uncertain:1

Jul 10, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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 cysteine, which is neutral and slightly polar, at codon 45 of the SCN1B protein (p.Arg45Cys). This variant is present in population databases (rs757554677, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with SCN1B-related conditions. ClinVar contains an entry for this variant (Variation ID: 436652). 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. -

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

Uncertain:1

Sep 13, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Uncertain:1

Oct 22, 2020

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Located within extracellular topological domain; Has not been previously published as pathogenic or benign to our knowledge -

Cardiovascular phenotype

Uncertain:1

Jun 05, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R45C variant (also known as c.133C>T), located in coding exon 2 of the SCN1B gene, results from a C to T substitution at nucleotide position 133. The arginine at codon 45 is replaced by cysteine, an amino acid with highly dissimilar properties. This variant was reported in individual(s) with features consistent with epilepsy (Nat Neurosci, 2024 Oct;27:1864-1879; Truty R et al. Epilepsia Open, 2019 Sep;4:397-408). This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.83

BayesDel_addAF

Uncertain

0.043

BayesDel_noAF

Uncertain

0.010

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.41

T;T;.;.;.;.

Eigen

Benign

-0.039

Eigen_PC

Benign

-0.12

FATHMM_MKL

Benign

0.73

LIST_S2

Pathogenic

0.97

.;D;D;D;D;D

M_CAP

Pathogenic

0.45

MetaRNN

Uncertain

0.54

D;D;D;D;D;D

MetaSVM

Uncertain

0.55

MutationAssessor

Benign

1.6

L;L;L;.;.;.

PhyloP100

3.3

PrimateAI

Uncertain

0.75

PROVEAN

Pathogenic

-4.4

D;.;D;.;.;.

REVEL

Uncertain

0.63

Sift

Uncertain

0.0020

D;.;D;.;.;.

Sift4G

Uncertain

0.0040

D;.;D;D;.;.

Polyphen

1.0

D;D;D;D;.;.

Vest4

0.42

MutPred

0.52

Loss of disorder (P = 0.0429);Loss of disorder (P = 0.0429);Loss of disorder (P = 0.0429);Loss of disorder (P = 0.0429);.;.;

MVP

0.96

MPC

1.8

ClinPred

0.96

GERP RS

2.8

PromoterAI

-0.0047

Neutral

(source)

Varity_R

0.64

gMVP

0.93

Mutation Taster

=69/31

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over