2-174759625-C-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 1P and 2B. PP2BP4_Moderate

The NM_000079.4(CHRNA1):c.52G>A(p.Val18Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000744 in 1,613,294 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V18L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

CHRNA1
NM_000079.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.22

Publications

0 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: Likely_benign. The variant received -1 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.

BP4

Computational evidence support a benign effect (MetaRNN=0.14549452).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA1	NM_000079.4 link	c.52G>A	p.Val18Ile	missense_variant	Exon 2 of 9	ENST00000348749.9	NP_000070.1	P02708-2Q53SH4
CHRNA1	NM_001039523.3 link	c.52G>A	p.Val18Ile	missense_variant	Exon 2 of 10		NP_001034612.1	P02708-1Q53SH4
CHRNA1	XM_017003256.2 link	c.73G>A	p.Val25Ile	missense_variant	Exon 1 of 9		XP_016858745.1
CHRNA1	XM_017003257.2 link	c.73G>A	p.Val25Ile	missense_variant	Exon 1 of 8		XP_016858746.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA1	ENST00000348749.9 link	c.52G>A	p.Val18Ile	missense_variant	Exon 2 of 9	1	NM_000079.4	ENSP00000261008.5		P02708-2

Frequencies

GnomAD3 genomes

AF:

0.0000395

AC:

AN:

151984

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000159

AC:

AN:

251042

AF XY:

0.00000737

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000411

AC:

AN:

1461310

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

726990

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33466

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.00

AC:

AN:

86242

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53250

Middle Eastern (MID)

AF:

0.000182

AC:

AN:

5490

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111952

Other (OTH)

AF:

0.0000166

AC:

AN:

60354

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.550

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:

0.0000395

AC:

AN:

151984

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74260

show subpopulations

African (AFR)

AF:

0.000145

AC:

AN:

41344

American (AMR)

AF:

0.00

AC:

AN:

15262

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10594

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2084

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:

0.0000331

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Lethal multiple pterygium syndrome

Uncertain:1

Dec 31, 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 isoleucine, which is neutral and non-polar, at codon 18 of the CHRNA1 protein (p.Val18Ile). This variant is present in population databases (rs202221890, gnomAD 0.02%). This variant has not been reported in the literature in individuals affected with CHRNA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1348872). 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 95%. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.10

BayesDel_addAF

Benign

-0.29

BayesDel_noAF

Benign

-0.42

CADD

Benign

(source)

DANN

Uncertain

0.98

DEOGEN2

Benign

0.19

.;T;T;T;T;.

Eigen

Benign

-0.25

Eigen_PC

Benign

-0.082

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.67

T;T;T;T;T;T

M_CAP

Benign

0.021

MetaRNN

Benign

0.15

T;T;T;T;T;T

MetaSVM

Benign

-0.37

MutationAssessor

Benign

1.5

L;L;.;.;.;.

PhyloP100

1.2

PrimateAI

Benign

0.39

PROVEAN

Benign

-0.30

N;N;N;N;.;N

REVEL

Benign

0.18

Sift

Benign

0.23

T;T;D;T;.;T

Sift4G

Benign

0.25

T;T;T;T;.;T

Polyphen

0.0040, 0.0070

.;B;.;.;.;B

Vest4

0.16

MVP

0.55

MPC

0.21

ClinPred

0.12

GERP RS

3.1

Varity_R

0.031

gMVP

0.24

Mutation Taster

=91/9

polymorphism

(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