rs762764855

Positions:

chr20-63350918-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_000744.7(CHRNA4):c.493G>A(p.Val165Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,752 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.74

Variant links:

Genes affected

CHRNA4 (HGNC:1958): (cholinergic receptor nicotinic alpha 4 subunit) This gene encodes a nicotinic acetylcholine receptor, which belongs to a superfamily of ligand-gated ion channels that play a role in fast signal transmission at synapses. These pentameric receptors can bind acetylcholine, which causes an extensive change in conformation that leads to the opening of an ion-conducting channel across the plasma membrane. This protein is an integral membrane receptor subunit that can interact with either nAChR beta-2 or nAChR beta-4 to form a functional receptor. Mutations in this gene cause nocturnal frontal lobe epilepsy type 1. Polymorphisms in this gene that provide protection against nicotine addiction have been described. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2012]

CHRNA4 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
CHRNA4	NM_000744.7 linkuse as main transcript	c.493G>A	p.Val165Ile	missense_variant	5/6	ENST00000370263.9
CHRNA4	NM_001256573.2 linkuse as main transcript	c.-36G>A		5_prime_UTR_variant	5/6
CHRNA4	NR_046317.2 linkuse as main transcript	n.702G>A		non_coding_transcript_exon_variant	5/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA4	ENST00000370263.9 linkuse as main transcript	c.493G>A	p.Val165Ile	missense_variant	5/6	1	NM_000744.7	P1	P43681-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251170

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135882

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:

0.0000653

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000205

AC:

AN:

1461752

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727152

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:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ExAC

AF:

0.0000165

AC:

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

Aug 30, 2023

This variant is present in population databases (rs762764855, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with CHRNA4-related conditions. ClinVar contains an entry for this variant (Variation ID: 411849). 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 CHRNA4 protein function. 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. This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 165 of the CHRNA4 protein (p.Val165Ile). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Benign

0.011

BayesDel_noAF

Uncertain

-0.040

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Benign

0.25

T;.

Eigen

Uncertain

0.58

Eigen_PC

Uncertain

0.59

FATHMM_MKL

Uncertain

0.94

LIST_S2

Uncertain

0.94

D;D

M_CAP

Uncertain

0.22

MetaRNN

Uncertain

0.49

T;T

MetaSVM

Uncertain

0.066

MutationAssessor

Benign

1.7

L;.

MutationTaster

Benign

1.0

PrimateAI

Pathogenic

0.81

PROVEAN

Benign

-0.57

N;.

REVEL

Uncertain

0.49

Sift

Benign

0.18

T;.

Sift4G

Benign

0.24

T;T

Polyphen

0.99

D;.

Vest4

0.62

MutPred

0.72

Loss of loop (P = 0.2237);.;

MVP

0.88

MPC

1.1

ClinPred

0.88

GERP RS

4.9

Varity_R

0.13

gMVP

0.59

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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