NM_000748.3:c.170C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BS2

The NM_000748.3(CHRNB2):c.170C>T(p.Thr57Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000867 in 1,614,132 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

CHRNB2
NM_000748.3 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 2.71

Publications

0 publications found

Variant links:

Genes affected

CHRNB2 (HGNC:1962): (cholinergic receptor nicotinic beta 2 subunit) Neuronal acetylcholine receptors are homo- or heteropentameric complexes composed of homologous alpha and beta subunits. They belong to a superfamily of ligand-gated ion channels which allow the flow of sodium and potassium across the plasma membrane in response to ligands such as acetylcholine and nicotine. This gene encodes one of several beta subunits. Mutations in this gene are associated with autosomal dominant nocturnal frontal lobe epilepsy. [provided by RefSeq, Jul 2008]

CHRNB2 Gene-Disease associations (from GenCC):

familial sleep-related hypermotor epilepsy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
autosomal dominant nocturnal frontal lobe epilepsy 3
Inheritance: AD Classification: STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
autosomal dominant nocturnal frontal lobe epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

CHRNB2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -4 ACMG points.

BS2

High AC in GnomAdExome4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNB2	NM_000748.3 link	c.170C>T	p.Thr57Ile	missense_variant	Exon 2 of 6	ENST00000368476.4	NP_000739.1
CHRNB2	XR_001736952.3 link	n.437C>T		non_coding_transcript_exon_variant	Exon 2 of 7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein
CHRNB2	ENST00000368476.4 link	c.170C>T	p.Thr57Ile	missense_variant	Exon 2 of 6	1	NM_000748.3	ENSP00000357461.3
CHRNB2	ENST00000637900.1 link	c.170C>T	p.Thr57Ile	missense_variant	Exon 2 of 6	5		ENSP00000490474.1
CHRNB2	ENST00000636034.1 link	n.170C>T		non_coding_transcript_exon_variant	Exon 2 of 9	5		ENSP00000489703.1
CHRNB2	ENST00000636695.1 link	n.40C>T		non_coding_transcript_exon_variant	Exon 1 of 3	5

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152162

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251368

AF XY:

0.00000736

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000868

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000821

AC:

AN:

1461850

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727230

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000894

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000719

AC:

AN:

1111988

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

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:

152282

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74458

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41542

American (AMR)

AF:

0.00

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.000288

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00340

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2104

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

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:

0.0000712

Hom.:

Bravo

AF:

0.00000378

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Oct 11, 2016

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy

Uncertain:1

Jan 27, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 57 of the CHRNB2 protein (p.Thr57Ile). This variant is present in population databases (no rsID available, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with CHRNB2-related conditions. ClinVar contains an entry for this variant (Variation ID: 447040). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt CHRNB2 protein function with a negative predictive value of 80%. 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. -

Inborn genetic diseases

Uncertain:1

Jul 07, 2024

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.170C>T (p.T57I) alteration is located in exon 2 (coding exon 2) of the CHRNB2 gene. This alteration results from a C to T substitution at nucleotide position 170, causing the threonine (T) at amino acid position 57 to be replaced by an isoleucine (I). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.24

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.28

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.57

D;.

Eigen

Uncertain

0.31

Eigen_PC

Uncertain

0.25

FATHMM_MKL

Benign

0.35

LIST_S2

Benign

0.78

T;T

M_CAP

Benign

0.055

MetaRNN

Uncertain

0.45

T;T

MetaSVM

Uncertain

-0.16

MutationAssessor

Benign

1.6

L;.

PhyloP100

2.7

PrimateAI

Uncertain

0.72

PROVEAN

Uncertain

-2.8

D;.

REVEL

Uncertain

0.41

Sift

Benign

0.32

T;.

Sift4G

Benign

0.31

T;.

Polyphen

0.99

D;.

Vest4

0.34

MutPred

0.53

Loss of sheet (P = 0.1158);Loss of sheet (P = 0.1158);

MVP

0.75

MPC

2.3

ClinPred

0.91

GERP RS

4.8

Varity_R

0.42

gMVP

0.76

Mutation Taster

=31/69

disease causing

(source)

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

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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