rs56175056

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP6BS2

The NM_000744.7(CHRNA4):​c.1006C>T​(p.Arg336Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000732 in 1,613,796 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00041 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00076 ( 1 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

3
11
5

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:5

Conservation

PhyloP100: 2.29
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -5 ACMG points.

BP6
Variant 20-63350405-G-A is Benign according to our data. Variant chr20-63350405-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 205020.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Uncertain_significance=2}. Variant chr20-63350405-G-A is described in Lovd as [Likely_benign].
BS2
High AC in GnomAd4 at 63 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA4NM_000744.7 linkc.1006C>T p.Arg336Cys missense_variant Exon 5 of 6 ENST00000370263.9 NP_000735.1 P43681-1B4DK78Q59FV0
CHRNA4NM_001256573.2 linkc.478C>T p.Arg160Cys missense_variant Exon 5 of 6 NP_001243502.1 P43681Q4VAQ3B4DK78Q59FV0
CHRNA4NR_046317.2 linkn.1215C>T non_coding_transcript_exon_variant Exon 5 of 6

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CHRNA4ENST00000370263.9 linkc.1006C>T p.Arg336Cys missense_variant Exon 5 of 6 1 NM_000744.7 ENSP00000359285.4 P43681-1

Frequencies

GnomAD3 genomes
AF:
0.000414
AC:
63
AN:
152220
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000362
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000654
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:
0.000691
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.000331
AC:
83
AN:
250798
Hom.:
0
AF XY:
0.000309
AC XY:
42
AN XY:
135826
show subpopulations
Gnomad AFR exome
AF:
0.000308
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:
0.000689
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000765
AC:
1118
AN:
1461576
Hom.:
1
Cov.:
99
AF XY:
0.000718
AC XY:
522
AN XY:
727082
show subpopulations
Gnomad4 AFR exome
AF:
0.000358
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:
0.000908
Gnomad4 OTH exome
AF:
0.00154
GnomAD4 genome
AF:
0.000414
AC:
63
AN:
152220
Hom.:
0
Cov.:
32
AF XY:
0.000376
AC XY:
28
AN XY:
74372
show subpopulations
Gnomad4 AFR
AF:
0.000362
Gnomad4 AMR
AF:
0.0000654
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.000691
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.000572
Hom.:
0
Bravo
AF:
0.000457
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00156
AC:
6
ESP6500AA
AF:
0.000454
AC:
2
ESP6500EA
AF:
0.000930
AC:
8
ExAC
AF:
0.000264
AC:
32
EpiCase
AF:
0.000927
EpiControl
AF:
0.000771

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:2Benign:5
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:1Benign:2
Jan 16, 2017
Eurofins Ntd Llc (ga)
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jan 14, 2021
GeneDx
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 24385388, 19058950, 26440539, 26952864) -

Nov 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

CHRNA4: BS1 -

Autosomal dominant nocturnal frontal lobe epilepsy 1 Uncertain:1
Aug 26, 2022
Revvity Omics, Revvity
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

CHRNA4-related disorder Benign:1
Nov 14, 2023
PreventionGenetics, part of Exact Sciences
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1
Jan 30, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Inborn genetic diseases Benign:1
Jan 29, 2019
Ambry Genetics
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.17
BayesDel_addAF
Benign
-0.19
T
BayesDel_noAF
Uncertain
-0.060
CADD
Uncertain
25
DANN
Pathogenic
1.0
DEOGEN2
Uncertain
0.68
D;.
Eigen
Uncertain
0.30
Eigen_PC
Uncertain
0.27
FATHMM_MKL
Uncertain
0.93
D
LIST_S2
Uncertain
0.97
D;D
M_CAP
Pathogenic
0.37
D
MetaRNN
Uncertain
0.64
D;D
MetaSVM
Uncertain
0.57
D
MutationAssessor
Pathogenic
3.0
M;.
PrimateAI
Uncertain
0.59
T
PROVEAN
Benign
-2.3
N;.
REVEL
Uncertain
0.54
Sift
Benign
0.031
D;.
Sift4G
Uncertain
0.027
D;D
Polyphen
0.85
P;.
Vest4
0.61
MVP
0.96
MPC
1.4
ClinPred
0.61
D
GERP RS
4.2
Varity_R
0.17
gMVP
0.53

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.

Other links and lift over

dbSNP: rs56175056; hg19: chr20-61981757; COSMIC: COSV64718620; COSMIC: COSV64718620; API