chr20-63350351-G-A

Position:

chr20-63350351-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PP3_ModerateBS2

The NM_000744.7(CHRNA4):c.1060C>T(p.Arg354Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000124 in 1,613,484 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R354H) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000012 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 6.45

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 Likely_benign. Variant got -2 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.891

BS2

High AC in GnomAdExome4 at 18 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
CHRNA4	NM_000744.7 linkuse as main transcript	c.1060C>T	p.Arg354Cys	missense_variant	5/6	ENST00000370263.9
CHRNA4	NM_001256573.2 linkuse as main transcript	c.532C>T	p.Arg178Cys	missense_variant	5/6
CHRNA4	NR_046317.2 linkuse as main transcript	n.1269C>T		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.1060C>T	p.Arg354Cys	missense_variant	5/6	1	NM_000744.7	P1	P43681-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152222

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:

0.00

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:

0.0000160

AC:

AN:

250418

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135724

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:

0.00000885

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000123

AC:

AN:

1461262

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

726932

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000464

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000108

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152222

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74366

show subpopulations

Gnomad4 AFR

AF:

0.0000241

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:

0.0000564

Hom.:

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy 1

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Revvity Omics, Revvity

Jul 22, 2021

- -

Autosomal dominant nocturnal frontal lobe epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 31, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 354 of the CHRNA4 protein (p.Arg354Cys). This variant is present in population databases (rs758534439, 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: 411846). 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Oct 01, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.16

BayesDel_addAF

Pathogenic

0.31

BayesDel_noAF

Pathogenic

0.38

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.81

D;.

Eigen

Pathogenic

0.69

Eigen_PC

Uncertain

0.63

FATHMM_MKL

Uncertain

0.93

LIST_S2

Uncertain

0.96

D;D

M_CAP

Pathogenic

0.34

MetaRNN

Pathogenic

0.89

D;D

MetaSVM

Pathogenic

0.81

MutationAssessor

Uncertain

2.9

M;.

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.61

PROVEAN

Pathogenic

-6.2

D;.

REVEL

Pathogenic

0.80

Sift

Pathogenic

0.0

D;.

Sift4G

Pathogenic

0.0010

D;D

Polyphen

0.99

D;.

Vest4

0.72

MutPred

0.61

Loss of MoRF binding (P = 0.0029);.;

MVP

0.95

MPC

1.4

ClinPred

0.99

GERP RS

5.2

Varity_R

0.68

gMVP

0.80

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