2-174754233-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PP2PP3_Moderate

The NM_000079.4(CHRNA1):c.526G>A(p.Val176Met) variant causes a missense change. The variant allele was found at a frequency of 0.000013 in 1,613,406 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 Uncertain significance (★★).

Frequency

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

Exomes 𝑓: 0.000013 ( 0 hom. )

Consequence

CHRNA1
NM_000079.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:2

Conservation

PhyloP100: 5.87

Publications

7 publications found

Variant links:

Genes affected

CHRNA1 (HGNC:1955): (cholinergic receptor nicotinic alpha 1 subunit) The muscle acetylcholine receptor consiststs of 5 subunits of 4 different types: 2 alpha subunits and 1 each of the beta, gamma, and delta subunits. This gene encodes an alpha subunit that plays a role in acetlycholine binding/channel gating. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Nov 2012]

CHRNA1 Gene-Disease associations (from GenCC):

congenital myasthenic syndrome 1A
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), PanelApp Australia
lethal multiple pterygium syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
myasthenic syndrome, congenital, 1B, fast-channel
Inheritance: AR, AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, PanelApp Australia
postsynaptic congenital myasthenic syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

CHRNA1 links:

ENSG00000236449 (HGNC:):

ENSG00000236449 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 3 ACMG points.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 16 curated pathogenic missense variants (we use a threshold of 10). The gene has 5 curated benign missense variants. Gene score misZ: 0.72157 (below the threshold of 3.09). Trascript score misZ: 1.6771 (below the threshold of 3.09). GenCC associations: The gene is linked to lethal multiple pterygium syndrome, congenital myasthenic syndrome 1A, myasthenic syndrome, congenital, 1B, fast-channel, postsynaptic congenital myasthenic syndrome.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.881

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
CHRNA1	NM_000079.4 link	c.526G>A	p.Val176Met	missense_variant	Exon 5 of 9	ENST00000348749.9	NP_000070.1
CHRNA1	NM_001039523.3 link	c.601G>A	p.Val201Met	missense_variant	Exon 6 of 10		NP_001034612.1
CHRNA1	XM_017003256.2 link	c.622G>A	p.Val208Met	missense_variant	Exon 5 of 9		XP_016858745.1
CHRNA1	XM_017003257.2 link	c.547G>A	p.Val183Met	missense_variant	Exon 4 of 8		XP_016858746.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA1	ENST00000348749.9 link	c.526G>A	p.Val176Met	missense_variant	Exon 5 of 9	1	NM_000079.4	ENSP00000261008.5

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152182

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000199

AC:

AN:

251334

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.0000993

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000130

AC:

AN:

1461224

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

726904

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33460

American (AMR)

AF:

0.0000224

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86224

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5348

European-Non Finnish (NFE)

AF:

0.0000117

AC:

AN:

1111920

Other (OTH)

AF:

0.0000497

AC:

AN:

60322

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.467

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:

152182

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74334

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41450

American (AMR)

AF:

0.00

AC:

AN:

15282

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10606

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2092

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:

0.0000191

Hom.:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Congenital myasthenic syndrome 1A

Pathogenic:1

May 01, 1997

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Lethal multiple pterygium syndrome

Uncertain:1

Oct 13, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 176 of the CHRNA1 protein (p.Val176Met). This variant is present in population databases (rs137852799, gnomAD 0.01%). This missense change has been observed in individual(s) with clinical features of autosomal dominant congenital myasthenic syndrome (PMID: 9158151). This variant is also known as p.Val156Met. ClinVar contains an entry for this variant (Variation ID: 18377). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt CHRNA1 protein function with a negative predictive value of 80%. Experimental studies have shown that this missense change affects CHRNA1 function (PMID: 9158151). 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. -

not provided

Uncertain:1

Jul 16, 2019

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.72

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.32

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.53

.;D;T;T;T;.

Eigen

Pathogenic

0.85

Eigen_PC

Pathogenic

0.82

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.97

D;D;D;D;D;D

M_CAP

Uncertain

0.12

MetaRNN

Pathogenic

0.88

D;D;D;D;D;D

MetaSVM

Uncertain

0.44

MutationAssessor

Uncertain

2.3

.;M;.;.;.;.

PhyloP100

5.9

PrimateAI

Uncertain

0.72

PROVEAN

Benign

-1.9

N;N;N;N;.;N

REVEL

Pathogenic

0.80

Sift

Uncertain

0.0010

D;D;D;T;.;T

Sift4G

Uncertain

0.016

D;D;D;D;.;D

Polyphen

1.0, 1.0

.;D;.;.;.;D

Vest4

0.82

MVP

0.92

MPC

0.87

ClinPred

0.91

GERP RS

5.8

Varity_R

0.73

gMVP

0.70

Mutation Taster

=3/97

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