2-174753595-C-T

Position:

chr2-174753595-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM5PP3_Strong

The NM_000079.4(CHRNA1):c.686G>A(p.Arg229His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000335 in 1,613,916 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a pathogenic 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. R229C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000035 ( 1 hom. )

Consequence

CHRNA1
NM_000079.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 7.86

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 links:

(HGNC:):

links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM5

Other missense variant is known to change same aminoacid residue: Variant chr2-174753595-C-A is described in Lovd as [Pathogenic].

PP3

MetaRNN computational evidence supports a deleterious effect, 0.989

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
CHRNA1	NM_000079.4 linkuse as main transcript	c.686G>A	p.Arg229His	missense_variant	6/9	ENST00000348749.9
CHRNA1	NM_001039523.3 linkuse as main transcript	c.761G>A	p.Arg254His	missense_variant	7/10
CHRNA1	XM_017003256.2 linkuse as main transcript	c.782G>A	p.Arg261His	missense_variant	6/9
CHRNA1	XM_017003257.2 linkuse as main transcript	c.707G>A	p.Arg236His	missense_variant	5/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA1	ENST00000348749.9 linkuse as main transcript	c.686G>A	p.Arg229His	missense_variant	6/9	1	NM_000079.4	P1	P02708-2
	ENST00000442996.1 linkuse as main transcript	n.322-19154C>T		intron_variant, non_coding_transcript_variant		1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152024

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:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251442

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135892

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000440

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000349

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.0000303

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000342

Gnomad4 OTH exome

AF:

0.0000828

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152024

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74246

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000111

Hom.:

Bravo

AF:

0.0000227

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.000109

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Lethal multiple pterygium syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 12, 2023	This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 229 of the CHRNA1 protein (p.Arg229His). This variant is present in population databases (rs137852809, gnomAD 0.01%). 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: 578690). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt CHRNA1 protein function with a positive predictive value of 80%. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Congenital myasthenic syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.57

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.93

.;D;D;D;T;.

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.94

FATHMM_MKL

Uncertain

0.93

LIST_S2

Pathogenic

0.99

D;D;D;D;D;D

M_CAP

Pathogenic

0.56

MetaRNN

Pathogenic

0.99

D;D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.1

.;H;.;.;.;.

MutationTaster

Benign

1.0

D;D;D;D;D

PrimateAI

Uncertain

0.76

PROVEAN

Pathogenic

-4.7

D;D;D;D;.;D

REVEL

Pathogenic

0.98

Sift

Pathogenic

0.0

D;D;D;D;.;D

Sift4G

Pathogenic

0.0

D;D;D;D;.;D

Polyphen

1.0

.;D;.;.;.;D

Vest4

0.98

MutPred

0.95

.;Loss of sheet (P = 0.302);.;.;.;.;

MVP

0.94

MPC

1.0

ClinPred

1.0

GERP RS

5.2

Varity_R

0.94

gMVP

0.96

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over