rs200644872

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 1P and 5B. PP3BP6BS2

The NM_000744.7(CHRNA4):​c.1757C>T​(p.Ser586Leu) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000422 in 1,612,642 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. S586S) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 34)
Exomes 𝑓: 0.000043 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense, splice_region

Scores

7
8
1
Splicing: ADA: 0.9472
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:2

Conservation

PhyloP100: 7.76

Publications

3 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 -4 ACMG points.

PP3
MetaRNN computational evidence supports a deleterious effect, 0.766
BP6
Variant 20-63349654-G-A is Benign according to our data. Variant chr20-63349654-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 205039.
BS2
High AC in GnomAd4 at 5 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA4NM_000744.7 linkc.1757C>T p.Ser586Leu missense_variant, splice_region_variant Exon 5 of 6 ENST00000370263.9 NP_000735.1
CHRNA4NM_001256573.2 linkc.1229C>T p.Ser410Leu missense_variant, splice_region_variant Exon 5 of 6 NP_001243502.1
CHRNA4NR_046317.2 linkn.1966C>T splice_region_variant, 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.1757C>T p.Ser586Leu missense_variant, splice_region_variant Exon 5 of 6 1 NM_000744.7 ENSP00000359285.4

Frequencies

GnomAD3 genomes
AF:
0.0000328
AC:
5
AN:
152240
Hom.:
0
Cov.:
34
show subpopulations
Gnomad AFR
AF:
0.0000965
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:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000161
AC:
4
AN:
247926
AF XY:
0.00000742
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000271
Gnomad OTH exome
AF:
0.000164
GnomAD4 exome
AF:
0.0000431
AC:
63
AN:
1460402
Hom.:
0
Cov.:
34
AF XY:
0.0000482
AC XY:
35
AN XY:
726526
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33470
American (AMR)
AF:
0.0000447
AC:
2
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26124
East Asian (EAS)
AF:
0.0000756
AC:
3
AN:
39692
South Asian (SAS)
AF:
0.0000696
AC:
6
AN:
86256
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
52156
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.0000405
AC:
45
AN:
1111854
Other (OTH)
AF:
0.0000994
AC:
6
AN:
60364
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.473
Heterozygous variant carriers
0
4
8
13
17
21
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:
0.0000328
AC:
5
AN:
152240
Hom.:
0
Cov.:
34
AF XY:
0.0000403
AC XY:
3
AN XY:
74378
show subpopulations
African (AFR)
AF:
0.0000965
AC:
4
AN:
41466
American (AMR)
AF:
0.0000654
AC:
1
AN:
15286
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10630
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.505
Heterozygous variant carriers
0
1
2
2
3
4
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:
0.0000901
Hom.:
0
Bravo
AF:
0.0000189
ExAC
AF:
0.0000247
AC:
3
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:3
Nov 01, 2022
CeGaT Center for Human Genetics Tuebingen
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

CHRNA4: PM2:Supporting

Dec 08, 2016
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

A variant of uncertain significance has been identified in the CHRNA4 gene. The S586L variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The S586L variant is not observed at a significant frequency in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). The S586L variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other 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 variants 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 variant or a rare benign variant.

Feb 01, 2016
Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1
May 15, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Inborn genetic diseases Benign:1
Jan 20, 2025
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
Pathogenic
0.26
D
BayesDel_noAF
Pathogenic
0.19
CADD
Pathogenic
29
DANN
Uncertain
1.0
DEOGEN2
Pathogenic
0.82
D;.
Eigen
Uncertain
0.59
Eigen_PC
Uncertain
0.54
LIST_S2
Pathogenic
0.98
D;D
M_CAP
Pathogenic
0.56
D
MetaRNN
Pathogenic
0.77
D;D
MetaSVM
Uncertain
0.63
D
MutationAssessor
Pathogenic
3.1
M;.
PhyloP100
7.8
PrimateAI
Uncertain
0.69
T
PROVEAN
Uncertain
-4.1
D;.
Sift
Uncertain
0.011
D;.
Sift4G
Uncertain
0.011
D;D
Vest4
0.70
ClinPred
0.91
D
GERP RS
4.9
Varity_R
0.26
gMVP
0.75
Mutation Taster
=16/84
disease causing

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Benign
0.95
dbscSNV1_RF
Benign
0.69
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: rs200644872; hg19: chr20-61981006; COSMIC: COSV64718633; COSMIC: COSV64718633; API