NM_000744.7:c.254C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 4P and 5B. PP3_StrongBP6BS2

The NM_000744.7(CHRNA4):c.254C>T(p.Thr85Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000749 in 1,601,270 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). Synonymous variant affecting the same amino acid position (i.e. T85T) has been classified as Likely benign.

Frequency

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

Exomes 𝑓: 0.0000069 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: 6.64

Publications

1 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: Likely_benign. The variant received -1 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.959

BP6

Variant 20-63356390-G-A is Benign according to our data. Variant chr20-63356390-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 377110.

BS2

High AC in GnomAdExome4 at 10 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA4	NM_000744.7 link	c.254C>T	p.Thr85Met	missense_variant	Exon 3 of 6	ENST00000370263.9	NP_000735.1	P43681-1B4DK78Q59FV0
CHRNA4	NM_001256573.2 link	c.-293C>T		5_prime_UTR_premature_start_codon_gain_variant	Exon 3 of 6		NP_001243502.1	P43681Q4VAQ3B4DK78Q59FV0
CHRNA4	NR_046317.2 link	n.438C>T		non_coding_transcript_exon_variant	Exon 3 of 6
CHRNA4	NM_001256573.2 link	c.-293C>T		5_prime_UTR_variant	Exon 3 of 6		NP_001243502.1	P43681Q4VAQ3B4DK78Q59FV0

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 link	c.254C>T	p.Thr85Met	missense_variant	Exon 3 of 6	1	NM_000744.7	ENSP00000359285.4		P43681-1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151962

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000174

AC:

AN:

229420

AF XY:

0.0000242

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000303

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000292

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000690

AC:

AN:

1449308

Hom.:

Cov.:

AF XY:

0.00000973

AC XY:

AN XY:

719484

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33314

American (AMR)

AF:

0.0000230

AC:

AN:

43548

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25806

East Asian (EAS)

AF:

0.00

AC:

AN:

39298

South Asian (SAS)

AF:

0.00

AC:

AN:

83800

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51336

Middle Eastern (MID)

AF:

0.000174

AC:

AN:

5750

European-Non Finnish (NFE)

AF:

0.00000723

AC:

AN:

1106578

Other (OTH)

AF:

0.00

AC:

AN:

59878

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.470

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:

0.0000132

AC:

AN:

151962

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74218

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41336

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5174

South Asian (SAS)

AF:

0.00

AC:

AN:

4814

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

67966

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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:

0.0000249

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Sep 02, 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; Has not been previously published as pathogenic or benign to our knowledge -

Apr 22, 2016

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Jan 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

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

Pathogenic

0.61

BayesDel_addAF

Pathogenic

0.32

BayesDel_noAF

Pathogenic

0.23

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.73

Eigen

Pathogenic

0.79

Eigen_PC

Pathogenic

0.68

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Pathogenic

0.99

M_CAP

Pathogenic

0.79

MetaRNN

Pathogenic

0.96

MetaSVM

Uncertain

0.78

MutationAssessor

Pathogenic

3.1

PhyloP100

6.6

PrimateAI

Pathogenic

0.83

PROVEAN

Pathogenic

-5.1

REVEL

Pathogenic

0.85

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.82

MutPred

0.77

Gain of MoRF binding (P = 0.1262);

MVP

0.93

MPC

1.2

ClinPred

0.99

GERP RS

4.3

Varity_R

0.71

gMVP

0.75

Mutation Taster

=24/76

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