chr20-63359703-C-T

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_000744.7(CHRNA4):c.77-4G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000299 in 1,610,160 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0013 ( 2 hom., cov: 34)

Exomes 𝑓: 0.00019 ( 3 hom. )

Consequence

CHRNA4
NM_000744.7 splice_region, intron

Scores

Splicing: ADA: 0.0001954

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4

Conservation

PhyloP100: -3.09

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: Benign. The variant received -9 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.76).

BP6

Variant 20-63359703-C-T is Benign according to our data. Variant chr20-63359703-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 136765.

BS2

High AC in GnomAd4 at 201 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
CHRNA4	NM_000744.7 link	c.77-4G>A	splice_region_variant, intron_variant	Intron 1 of 5	ENST00000370263.9	NP_000735.1	P43681-1B4DK78Q59FV0
CHRNA4	NM_001256573.2 link	c.-470-4G>A	splice_region_variant, intron_variant	Intron 1 of 5		NP_001243502.1	P43681Q4VAQ3B4DK78Q59FV0
CHRNA4	NR_046317.2 link	n.261-4G>A	splice_region_variant, intron_variant	Intron 1 of 5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 link	c.77-4G>A		splice_region_variant, intron_variant	Intron 1 of 5	1	NM_000744.7	ENSP00000359285.4		P43681-1

Frequencies

GnomAD3 genomes

AF:

0.00130

AC:

198

AN:

152120

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00444

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000393

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000621

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.000958

GnomAD2 exomes

AF:

0.000299

AC:

AN:

247124

AF XY:

0.000223

show subpopulations

Gnomad AFR exome

AF:

0.00403

Gnomad AMR exome

AF:

0.000174

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:

0.000165

GnomAD4 exome

AF:

0.000193

AC:

281

AN:

1457920

Hom.:

Cov.:

AF XY:

0.000163

AC XY:

118

AN XY:

725288

show subpopulations

African (AFR)

AF:

0.00622

AC:

208

AN:

33426

American (AMR)

AF:

0.000291

AC:

AN:

44696

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26112

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.0000928

AC:

AN:

86168

European-Finnish (FIN)

AF:

0.00

AC:

AN:

51548

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4416

European-Non Finnish (NFE)

AF:

0.00000989

AC:

AN:

1111704

Other (OTH)

AF:

0.000681

AC:

AN:

60162

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.00132

AC:

201

AN:

152240

Hom.:

Cov.:

AF XY:

0.00130

AC XY:

AN XY:

74430

show subpopulations

African (AFR)

AF:

0.00450

AC:

187

AN:

41542

American (AMR)

AF:

0.000392

AC:

AN:

15306

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5168

South Asian (SAS)

AF:

0.000621

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

67996

Other (OTH)

AF:

0.000948

AC:

AN:

2110

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:

0.000639

Hom.:

Bravo

AF:

0.00136

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Dec 02, 2014

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

CHRNA4: BS1, BS2 -

not specified

Benign:1

Mar 25, 2014

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

Jun 22, 2021

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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.76

CADD

Benign

0.12

(source)

DANN

Benign

0.87

PhyloP100

-3.1

Mutation Taster

=100/0

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00020

dbscSNV1_RF

Benign

0.0

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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