19-35033964-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBS1_Supporting

The ENST00000415950.5(SCN1B):c.673C>T(p.Arg225Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000663 in 1,552,498 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. 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. R225P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000066 ( 1 hom. )

Consequence

SCN1B
ENST00000415950.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: -0.378

Publications

2 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: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.03603211).

BS1

Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.0000657 (92/1400142) while in subpopulation MID AF = 0.000702 (4/5698). AF 95% confidence interval is 0.000239. There are 1 homozygotes in GnomAdExome4. There are 54 alleles in the male GnomAdExome4 subpopulation. Median coverage is 33. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SCN1B	NM_001037.5 link	c.448+225C>T		intron_variant	Intron 3 of 5	ENST00000262631.11	NP_001028.1	Q07699-1
SCN1B	NM_199037.5 link	c.673C>T	p.Arg225Cys	missense_variant	Exon 3 of 3		NP_950238.1	Q07699-2
SCN1B	NM_001321605.2 link	c.349+225C>T		intron_variant	Intron 3 of 5		NP_001308534.1	Q07699A0A1W2PR05

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SCN1B	ENST00000262631.11 link	c.448+225C>T		intron_variant	Intron 3 of 5	1	NM_001037.5	ENSP00000262631.3		Q07699-1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000122

AC:

AN:

156104

AF XY:

0.000109

show subpopulations

Gnomad AFR exome

AF:

0.000246

Gnomad AMR exome

AF:

0.000202

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000115

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000657

AC:

AN:

1400142

Hom.:

Cov.:

AF XY:

0.0000782

AC XY:

AN XY:

690716

show subpopulations

African (AFR)

AF:

0.000127

AC:

AN:

31608

American (AMR)

AF:

0.000168

AC:

AN:

35758

Ashkenazi Jewish (ASJ)

AF:

0.0000397

AC:

AN:

25186

East Asian (EAS)

AF:

0.0000280

AC:

AN:

35750

South Asian (SAS)

AF:

0.000239

AC:

AN:

79522

European-Finnish (FIN)

AF:

0.0000203

AC:

AN:

49352

Middle Eastern (MID)

AF:

0.000702

AC:

AN:

5698

European-Non Finnish (NFE)

AF:

0.0000491

AC:

AN:

1079226

Other (OTH)

AF:

0.0000517

AC:

AN:

58042

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.0000722

AC:

AN:

152356

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74510

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41576

American (AMR)

AF:

0.000131

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.000207

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.498

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:

0.000154

Hom.:

Bravo

AF:

0.000117

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000227

AC:

ExAC

AF:

0.0000615

AC:

Asia WGS

AF:

0.000577

AC:

AN:

3478

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Feb 24, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: SCN1B c.673C>T (p.Arg225Cys) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00012 in 156104 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in SCN1B causing SCN1B-Related Disorders, allowing no conclusion about variant significance. c.673C>T has been reported in the literature in a case of sudden infant death syndrome (example: Neubauer_2018). These report(s) do not provide unequivocal conclusions about association of the variant with SCN1B-Related Disorders. At least one publication reports experimental evidence that this variant has a loss of function effect on sodium current, however, does not allow convincing conclusions about the variant effect (example: Neubauer_2018). The following publication has been ascertained in the context of this evaluation (PMID: 29915715). ClinVar contains an entry for this variant (Variation ID: 242250). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Brugada syndrome 5

Uncertain:1

Nov 25, 2024

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 225 of the SCN1B protein (p.Arg225Cys). This variant is present in population databases (rs369588692, gnomAD 0.02%). This missense change has been observed in individual(s) with sudden infant death syndrome (PMID: 28074886, 29915715). ClinVar contains an entry for this variant (Variation ID: 242250). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The cysteine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Experimental studies have shown that this missense change affects SCN1B function (PMID: 29915715). 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. -

not provided

Uncertain:1

Apr 29, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported in a case of sudden infant death syndrome; no cardiac abnormalities were noted on autopsy (PMID: 29915715, 28074886); Electrophysiological studies suggest that p.(R225C) has a loss of function effect on sodium current; however, further studies are needed to confirm this finding (PMID: 29915715); In silico analysis indicates that this variant does not alter splicing; Reported using an alternate transcript of the gene; This variant is associated with the following publications: (PMID: 28074886, 29915715) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.092

BayesDel_addAF

Benign

-0.36

BayesDel_noAF

Benign

-0.46

CADD

Benign

0.59

(source)

DANN

Benign

0.52

Eigen

Benign

-1.9

Eigen_PC

Benign

-2.1

FATHMM_MKL

Benign

0.0083

LIST_S2

Benign

0.49

T;T

M_CAP

Uncertain

0.21

MetaRNN

Benign

0.036

T;T

MetaSVM

Benign

-0.74

PhyloP100

-0.38

PrimateAI

Benign

0.22

PROVEAN

Benign

-0.48

N;.

REVEL

Benign

0.14

Sift

Uncertain

0.013

D;.

Sift4G

Uncertain

0.029

D;.

Polyphen

0.0

B;.

Vest4

0.093

MVP

0.20

MPC

0.91

ClinPred

0.079

GERP RS

-6.8

gMVP

0.19

Mutation Taster

=99/1

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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