20-63346797-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4BP6_Very_StrongBS2

The NM_000744.7(CHRNA4):c.1825G>A(p.Val609Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000682 in 1,612,624 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V609F) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000064 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: 7.71

Publications

2 publications found

Variant links:

Genes affected

CHRNA4 (HGNC:1958): (cholinergic receptor nicotinic alpha 4 subunit) This gene encodes a nicotinic acetylcholine receptor, which belongs to a superfamily of ligand-gated ion channels that play a role in fast signal transmission at synapses. These pentameric receptors can bind acetylcholine, which causes an extensive change in conformation that leads to the opening of an ion-conducting channel across the plasma membrane. This protein is an integral membrane receptor subunit that can interact with either nAChR beta-2 or nAChR beta-4 to form a functional receptor. Mutations in this gene cause nocturnal frontal lobe epilepsy type 1. Polymorphisms in this gene that provide protection against nicotine addiction have been described. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2012]

CHRNA4 Gene-Disease associations (from GenCC):

autosomal dominant nocturnal frontal lobe epilepsy 1
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
familial sleep-related hypermotor epilepsy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
autosomal dominant nocturnal frontal lobe epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

CHRNA4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.41592833).

BP6

Variant 20-63346797-C-T is Benign according to our data. Variant chr20-63346797-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 205040.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS2

High AC in GnomAd4 at 17 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
CHRNA4	NM_000744.7 link	c.1825G>A	p.Val609Ile	missense_variant	Exon 6 of 6	ENST00000370263.9	NP_000735.1
CHRNA4	NM_001256573.2 link	c.1297G>A	p.Val433Ile	missense_variant	Exon 6 of 6		NP_001243502.1
CHRNA4	NR_046317.2 link	n.2034G>A		non_coding_transcript_exon_variant	Exon 6 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 link	c.1825G>A	p.Val609Ile	missense_variant	Exon 6 of 6	1	NM_000744.7	ENSP00000359285.4

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

152202

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000188

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000735

Gnomad OTH

AF:

0.000955

GnomAD2 exomes

AF:

0.0000889

AC:

AN:

247526

AF XY:

0.0000744

show subpopulations

Gnomad AFR exome

AF:

0.0000620

Gnomad AMR exome

AF:

0.000231

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad FIN exome

AF:

0.000279

Gnomad NFE exome

AF:

0.0000544

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000637

AC:

AN:

1460304

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

726492

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33454

American (AMR)

AF:

0.000291

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26118

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.000115

AC:

AN:

52298

Middle Eastern (MID)

AF:

0.000347

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.0000558

AC:

AN:

1111674

Other (OTH)

AF:

0.000166

AC:

AN:

60348

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

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:

0.000112

AC:

AN:

152320

Hom.:

Cov.:

AF XY:

0.000107

AC XY:

AN XY:

74472

show subpopulations

African (AFR)

AF:

0.0000722

AC:

AN:

41570

American (AMR)

AF:

0.000131

AC:

AN:

15308

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.000188

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00680

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000735

AC:

AN:

68024

Other (OTH)

AF:

0.000945

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.506

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:

0.0000559

Hom.:

Bravo

AF:

0.000147

ExAC

AF:

0.0000494

AC:

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Jan 30, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Jan 31, 2023

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

not provided

Benign:1

Apr 08, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

0.0038

BayesDel_noAF

Uncertain

0.060

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.37

T;.

Eigen

Uncertain

0.57

Eigen_PC

Uncertain

0.51

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.90

D;D

M_CAP

Pathogenic

0.46

MetaRNN

Benign

0.42

T;T

MetaSVM

Uncertain

0.67

MutationAssessor

Uncertain

2.4

M;.

PhyloP100

7.7

PrimateAI

Uncertain

0.55

PROVEAN

Benign

-0.69

N;.

REVEL

Pathogenic

0.65

Sift

Uncertain

0.022

D;.

Sift4G

Uncertain

0.028

D;D

Polyphen

1.0

D;.

Vest4

0.49

MutPred

0.60

Loss of catalytic residue at V609 (P = 0.1282);.;

MVP

0.89

MPC

0.81

ClinPred

0.21

GERP RS

4.4

Varity_R

0.11

gMVP

0.75

Mutation Taster

=32/68

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