NM_000742.4:c.1234G>A

Variant names:

Variant summary

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

The NM_000742.4(CHRNA2):c.1234G>A(p.Glu412Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000411 in 1,589,450 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00039 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00041 ( 1 hom. )

Consequence

CHRNA2
NM_000742.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:4

Conservation

PhyloP100: 0.785

Publications

4 publications found

Variant links:

Genes affected

CHRNA2 (HGNC:1956): (cholinergic receptor nicotinic alpha 2 subunit) Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels formed by a pentameric arrangement of alpha and beta subunits to create distinct muscle and neuronal receptors. Neuronal receptors are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. This gene encodes an alpha subunit that is widely expressed in the brain. The proposed structure for nAChR subunits is a conserved N-terminal extracellular domain followed by three conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region. Mutations in this gene cause autosomal dominant nocturnal frontal lobe epilepsy type 4. Single nucleotide polymorphisms (SNPs) in this gene have been associated with nicotine dependence. [provided by RefSeq, Nov 2009]

CHRNA2 Gene-Disease associations (from GenCC):

autosomal dominant nocturnal frontal lobe epilepsy 4
Inheritance: AD Classification: STRONG, LIMITED Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae)
autosomal dominant nocturnal frontal lobe epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
familial sleep-related hypermotor epilepsy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
benign familial infantile epilepsy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

CHRNA2 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 (MetaRNN=0.019646138).

BP6

Variant 8-27463209-C-T is Benign according to our data. Variant chr8-27463209-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 128736.

BS2

High AC in GnomAd4 at 60 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA2	NM_000742.4 link	c.1234G>A	p.Glu412Lys	missense_variant	Exon 6 of 7	ENST00000407991.3	NP_000733.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA2	ENST00000407991.3 link	c.1234G>A	p.Glu412Lys	missense_variant	Exon 6 of 7	5	NM_000742.4	ENSP00000385026.1

Frequencies

GnomAD3 genomes

AF:

0.000394

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000193

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00141

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000500

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000603

AC:

142

AN:

235312

AF XY:

0.000611

show subpopulations

Gnomad AFR exome

AF:

0.000247

Gnomad AMR exome

AF:

0.000326

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00181

Gnomad NFE exome

AF:

0.000592

Gnomad OTH exome

AF:

0.000872

GnomAD4 exome

AF:

0.000413

AC:

594

AN:

1437108

Hom.:

Cov.:

AF XY:

0.000430

AC XY:

306

AN XY:

710970

show subpopulations

African (AFR)

AF:

0.0000604

AC:

AN:

33108

American (AMR)

AF:

0.000320

AC:

AN:

43794

Ashkenazi Jewish (ASJ)

AF:

0.0000411

AC:

AN:

24318

East Asian (EAS)

AF:

0.00

AC:

AN:

39334

South Asian (SAS)

AF:

0.000654

AC:

AN:

82564

European-Finnish (FIN)

AF:

0.00154

AC:

AN:

52514

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5640

European-Non Finnish (NFE)

AF:

0.000383

AC:

420

AN:

1096610

Other (OTH)

AF:

0.000371

AC:

AN:

59226

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

122

162

203

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

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:

0.000394

AC:

AN:

152342

Hom.:

Cov.:

AF XY:

0.000443

AC XY:

AN XY:

74498

show subpopulations

African (AFR)

AF:

0.000192

AC:

AN:

41578

American (AMR)

AF:

0.00

AC:

AN:

15304

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.000193

AC:

AN:

5172

South Asian (SAS)

AF:

0.000414

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00141

AC:

AN:

10628

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000500

AC:

AN:

68040

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

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:

0.000456

Hom.:

Bravo

AF:

0.000295

ESP6500AA

AF:

0.000454

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000552

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Oct 14, 2016

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 15, 2014

Genetic Services Laboratory, University of Chicago

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 25, 2019

GeneDx

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Jan 06, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Inborn genetic diseases

Benign:1

May 18, 2022

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. -

Autosomal dominant nocturnal frontal lobe epilepsy 4

Benign:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.094

BayesDel_addAF

Benign

-0.33

BayesDel_noAF

Benign

-0.33

CADD

Benign

(source)

DANN

Benign

0.78

DEOGEN2

Benign

0.22

T;.;.

Eigen

Benign

-0.73

Eigen_PC

Benign

-0.71

FATHMM_MKL

Benign

0.26

LIST_S2

Benign

0.61

T;T;T

M_CAP

Uncertain

0.14

MetaRNN

Benign

0.020

T;T;T

MetaSVM

Benign

-0.70

MutationAssessor

Benign

1.3

L;.;.

PhyloP100

0.79

PrimateAI

Benign

0.35

PROVEAN

Benign

-0.27

N;.;N

REVEL

Uncertain

0.30

Sift

Benign

0.52

T;.;T

Sift4G

Benign

0.41

T;T;T

Polyphen

0.0090

B;.;.

Vest4

0.22

MVP

0.91

MPC

0.21

ClinPred

0.0036

GERP RS

4.6

Varity_R

0.11

gMVP

0.46

Mutation Taster

=86/14

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