8-27461688-C-T

Position:

chr8-27461688-C-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4BS2

The NM_000742.4(CHRNA2):c.1531G>A(p.Val511Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,218 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 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. V511L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

CHRNA2
NM_000742.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 3.42

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 -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.2755381).

BS2

High AC in GnomAdExome4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA2	NM_000742.4 linkuse as main transcript	c.1531G>A	p.Val511Ile	missense_variant	7/7	ENST00000407991.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA2	ENST00000407991.3 linkuse as main transcript	c.1531G>A	p.Val511Ile	missense_variant	7/7	5	NM_000742.4	P2	Q15822-1

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152214

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

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

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251478

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135920

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000547

AC:

AN:

1461886

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727244

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000360

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152332

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74484

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 18, 2022

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 not expected to disrupt CHRNA2 protein function. ClinVar contains an entry for this variant (Variation ID: 572660). This variant has not been reported in the literature in individuals affected with CHRNA2-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.007%). This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 511 of the CHRNA2 protein (p.Val511Ile). -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 13, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.22

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Benign

0.30

T;.;.

Eigen

Benign

0.0054

Eigen_PC

Benign

0.12

FATHMM_MKL

Uncertain

0.92

LIST_S2

Uncertain

0.91

D;D;D

M_CAP

Benign

0.061

MetaRNN

Benign

0.28

T;T;T

MetaSVM

Uncertain

-0.0060

MutationAssessor

Benign

1.9

L;.;.

MutationTaster

Benign

1.0

D;D;D

PrimateAI

Uncertain

0.50

PROVEAN

Benign

-0.75

N;N;N

REVEL

Uncertain

0.32

Sift

Uncertain

0.014

D;T;D

Sift4G

Uncertain

0.050

T;T;T

Polyphen

0.11

B;.;.

Vest4

0.22

MutPred

0.56

Loss of catalytic residue at V511 (P = 0.021);.;.;

MVP

0.88

MPC

0.21

ClinPred

0.83

GERP RS

3.0

Varity_R

0.25

gMVP

0.69

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