8-27469841-G-A

Position:

chr8-27469841-G-A

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 0P and 4B. BS2

The NM_000742.4(CHRNA2):c.214C>T(p.Arg72Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,614,062 control chromosomes in the GnomAD database, including 1 homozygotes. 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. R72H) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 1 hom. )

Consequence

CHRNA2
NM_000742.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.972

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

BS2

High AC in GnomAdExome4 at 21 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA2	NM_000742.4 linkuse as main transcript	c.214C>T	p.Arg72Cys	missense_variant	3/7	ENST00000407991.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA2	ENST00000407991.3 linkuse as main transcript	c.214C>T	p.Arg72Cys	missense_variant	3/7	5	NM_000742.4	P2	Q15822-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152210

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251410

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135900

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000653

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1461852

Hom.:

Cov.:

AF XY:

0.0000165

AC XY:

AN XY:

727228

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000671

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000580

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000117

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152210

Hom.:

Cov.:

AF XY:

0.0000134

AC XY:

AN XY:

74360

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:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000247

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 17, 2023

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. 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 CHRNA2 protein function. ClinVar contains an entry for this variant (Variation ID: 543519). This missense change has been observed in at least one individual who was not affected with CHRNA2-related conditions (Invitae). This variant has not been reported in the literature in individuals affected with CHRNA2-related conditions. This variant is present in population databases (rs201890355, gnomAD 0.009%). This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 72 of the CHRNA2 protein (p.Arg72Cys). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.31

BayesDel_addAF

Benign

-0.13

BayesDel_noAF

Benign

-0.23

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.78

D;.;.;.;.

Eigen

Uncertain

0.42

Eigen_PC

Uncertain

0.39

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.94

D;D;D;D;D

M_CAP

Benign

0.070

MetaRNN

Uncertain

0.52

D;D;D;D;D

MetaSVM

Benign

-0.42

MutationAssessor

Benign

2.0

M;.;M;.;.

MutationTaster

Benign

1.0

D;D;D

PrimateAI

Uncertain

0.64

PROVEAN

Pathogenic

-4.6

D;.;D;D;D

REVEL

Uncertain

0.39

Sift

Pathogenic

0.0

D;.;D;D;D

Sift4G

Pathogenic

0.0010

D;D;D;.;D

Polyphen

1.0

D;.;.;.;.

Vest4

0.56

MVP

0.79

MPC

0.85

ClinPred

0.89

GERP RS

3.9

Varity_R

0.79

gMVP

0.66

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