rs200243948

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2

The NM_000744.7(CHRNA4):​c.1430C>T​(p.Ala477Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000451 in 1,551,480 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A477A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000059 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000044 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

1
18

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:1

Conservation

PhyloP100: -1.55

Publications

0 publications found
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 Gene-Disease associations (from GenCC):
  • autosomal dominant nocturnal frontal lobe epilepsy 1
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
  • familial sleep-related hypermotor epilepsy
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • autosomal dominant nocturnal frontal lobe epilepsy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.07253635).
BP6
Variant 20-63349981-G-A is Benign according to our data. Variant chr20-63349981-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 205030.
BS2
High AC in GnomAd4 at 9 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA4NM_000744.7 linkc.1430C>T p.Ala477Val missense_variant Exon 5 of 6 ENST00000370263.9 NP_000735.1 P43681-1B4DK78Q59FV0
CHRNA4NM_001256573.2 linkc.902C>T p.Ala301Val missense_variant Exon 5 of 6 NP_001243502.1 P43681Q4VAQ3B4DK78Q59FV0
CHRNA4NR_046317.2 linkn.1639C>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.1430C>T p.Ala477Val missense_variant Exon 5 of 6 1 NM_000744.7 ENSP00000359285.4 P43681-1

Frequencies

GnomAD3 genomes
AF:
0.0000591
AC:
9
AN:
152240
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000724
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000654
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.000193
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.0000941
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000243
AC:
4
AN:
164284
AF XY:
0.0000225
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000394
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000293
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000436
AC:
61
AN:
1399240
Hom.:
0
Cov.:
83
AF XY:
0.0000450
AC XY:
31
AN XY:
689420
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
32224
American (AMR)
AF:
0.0000271
AC:
1
AN:
36894
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
24278
East Asian (EAS)
AF:
0.0000269
AC:
1
AN:
37216
South Asian (SAS)
AF:
0.0000761
AC:
6
AN:
78814
European-Finnish (FIN)
AF:
0.0000629
AC:
3
AN:
47680
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5486
European-Non Finnish (NFE)
AF:
0.0000445
AC:
48
AN:
1078934
Other (OTH)
AF:
0.0000347
AC:
2
AN:
57714
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.478
Heterozygous variant carriers
0
4
8
12
16
20
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000591
AC:
9
AN:
152240
Hom.:
0
Cov.:
33
AF XY:
0.0000672
AC XY:
5
AN XY:
74374
show subpopulations
African (AFR)
AF:
0.0000724
AC:
3
AN:
41464
American (AMR)
AF:
0.0000654
AC:
1
AN:
15290
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.000193
AC:
1
AN:
5192
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4838
European-Finnish (FIN)
AF:
0.0000941
AC:
1
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000441
AC:
3
AN:
68040
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.458
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000196
Hom.:
0
Bravo
AF:
0.0000302
ExAC
AF:
0.0000169
AC:
2

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:2Benign:1
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy 1;C1861063:Tobacco addiction, susceptibility to Uncertain:1
Oct 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Dec 26, 2017
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The A477V variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The A477V variant is not observed in large population cohorts (Lek et al., 2016). The A477V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This amino acid substitution is not predicted to occur within the transmembrane region of the protein, where the vast majority of pathogenic missense variants have been identified in association with epilepsy (Steinlein et al., 2010). In-silico analyses, including protein predictors and evolutionary conservation, support that this variant does not alter protein structure/function. Based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1
Aug 21, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.072
BayesDel_addAF
Benign
-0.20
T
BayesDel_noAF
Benign
-0.52
CADD
Benign
4.2
DANN
Benign
0.50
DEOGEN2
Benign
0.22
T;.
Eigen
Benign
-1.3
Eigen_PC
Benign
-1.4
FATHMM_MKL
Benign
0.061
N
LIST_S2
Benign
0.64
T;T
M_CAP
Uncertain
0.14
D
MetaRNN
Benign
0.073
T;T
MetaSVM
Benign
-0.91
T
MutationAssessor
Benign
0.66
N;.
PhyloP100
-1.6
PrimateAI
Benign
0.33
T
PROVEAN
Benign
-0.010
N;.
REVEL
Benign
0.15
Sift
Benign
0.28
T;.
Sift4G
Benign
0.42
T;T
Polyphen
0.0040
B;.
Vest4
0.065
MVP
0.65
MPC
0.40
ClinPred
0.036
T
GERP RS
-3.3
Varity_R
0.038
gMVP
0.23
Mutation Taster
=95/5
polymorphism

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

Other links and lift over

dbSNP: rs200243948; hg19: chr20-61981333; COSMIC: COSV100937524; COSMIC: COSV100937524; API