rs76895198

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP6BS2

The NM_000744.7(CHRNA4):​c.1700C>T​(p.Ala567Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000453 in 1,612,842 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A567G) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 34)
Exomes 𝑓: 0.000049 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

2
12
5

Clinical Significance

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

Conservation

PhyloP100: 9.64

Publications

12 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: Likely_benign. The variant received -5 ACMG points.

BP6
Variant 20-63349711-G-A is Benign according to our data. Variant chr20-63349711-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 205036.
BS2
High AC in GnomAdExome4 at 71 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA4NM_000744.7 linkc.1700C>T p.Ala567Val missense_variant Exon 5 of 6 ENST00000370263.9 NP_000735.1 P43681-1B4DK78Q59FV0
CHRNA4NM_001256573.2 linkc.1172C>T p.Ala391Val missense_variant Exon 5 of 6 NP_001243502.1 P43681Q4VAQ3B4DK78Q59FV0
CHRNA4NR_046317.2 linkn.1909C>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.1700C>T p.Ala567Val missense_variant Exon 5 of 6 1 NM_000744.7 ENSP00000359285.4 P43681-1

Frequencies

GnomAD3 genomes
AF:
0.0000131
AC:
2
AN:
152252
Hom.:
0
Cov.:
34
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000131
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000725
AC:
18
AN:
248240
AF XY:
0.0000815
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000376
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000109
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000180
Gnomad OTH exome
AF:
0.000165
GnomAD4 exome
AF:
0.0000486
AC:
71
AN:
1460472
Hom.:
0
Cov.:
34
AF XY:
0.0000399
AC XY:
29
AN XY:
726562
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33468
American (AMR)
AF:
0.000224
AC:
10
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26122
East Asian (EAS)
AF:
0.0000756
AC:
3
AN:
39690
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86254
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52234
Middle Eastern (MID)
AF:
0.000347
AC:
2
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000459
AC:
51
AN:
1111856
Other (OTH)
AF:
0.0000828
AC:
5
AN:
60362
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.481
Heterozygous variant carriers
0
4
9
13
18
22
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:
0.0000131
AC:
2
AN:
152370
Hom.:
0
Cov.:
34
AF XY:
0.0000268
AC XY:
2
AN XY:
74506
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41576
American (AMR)
AF:
0.000131
AC:
2
AN:
15312
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4826
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68044
Other (OTH)
AF:
0.00
AC:
0
AN:
2116
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.550
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000262
Hom.:
0
Bravo
AF:
0.0000151
ExAC
AF:
0.0000413
AC:
5
EpiCase
AF:
0.000164
EpiControl
AF:
0.00

ClinVar

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

Submissions by phenotype

not provided Uncertain:1
Jan 06, 2015
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

p.Ala567Val (GCG>GTG): c.1700 C>T in exon 5 of the CHRNA4 gene (NM_000744.5) The A567V variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The A567V variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. However, this amino acid substitution is not predicted to occur within the transmembrane region of the protein, where the vast majority of pathogenic missense mutations have been identified in association with epilepsy (Steinlein et al., 2010). Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. The variant is found in CHILD-EPIV2-1 panel(s). -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1
Dec 22, 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
Pathogenic
0.67
BayesDel_addAF
Benign
-0.0078
T
BayesDel_noAF
Uncertain
0.070
CADD
Uncertain
25
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.75
D;.
Eigen
Uncertain
0.34
Eigen_PC
Uncertain
0.30
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.93
D;D
M_CAP
Uncertain
0.18
D
MetaRNN
Uncertain
0.69
D;D
MetaSVM
Benign
-0.29
T
MutationAssessor
Uncertain
2.6
M;.
PhyloP100
9.6
PrimateAI
Uncertain
0.69
T
PROVEAN
Uncertain
-3.0
D;.
REVEL
Uncertain
0.49
Sift
Benign
0.22
T;.
Sift4G
Benign
0.12
T;T
Polyphen
0.63
P;.
Vest4
0.75
MutPred
0.64
Loss of disorder (P = 0.1212);.;
MVP
0.74
MPC
0.56
ClinPred
0.26
T
GERP RS
4.7
Varity_R
0.23
gMVP
0.87
Mutation Taster
=35/65
disease causing

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: rs76895198; hg19: chr20-61981063; COSMIC: COSV64718380; COSMIC: COSV64718380; API