rs145238683

Variant summary

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

The NM_000742.4(CHRNA2):​c.1568C>T​(p.Pro523Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000514 in 1,614,242 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P523R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000052 ( 0 hom. )

Consequence

CHRNA2
NM_000742.4 missense

Scores

6
12
1

Clinical Significance

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

Conservation

PhyloP100: 10.0

Publications

4 publications found
Variant links:
Genes affected
CHRNA2 (HGNC:1956): (cholinergic receptor nicotinic alpha 2 subunit) Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels formed by a pentameric arrangement of alpha and beta subunits to create distinct muscle and neuronal receptors. Neuronal receptors are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. This gene encodes an alpha subunit that is widely expressed in the brain. The proposed structure for nAChR subunits is a conserved N-terminal extracellular domain followed by three conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region. Mutations in this gene cause autosomal dominant nocturnal frontal lobe epilepsy type 4. Single nucleotide polymorphisms (SNPs) in this gene have been associated with nicotine dependence. [provided by RefSeq, Nov 2009]
CHRNA2 Gene-Disease associations (from GenCC):
  • autosomal dominant nocturnal frontal lobe epilepsy 4
    Inheritance: AD Classification: STRONG, LIMITED Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae)
  • autosomal dominant nocturnal frontal lobe epilepsy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • familial sleep-related hypermotor epilepsy
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen
  • benign familial infantile epilepsy
    Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

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, 0.812
BP6
Variant 8-27461651-G-A is Benign according to our data. Variant chr8-27461651-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 204977.
BS2
High AC in GnomAd4 at 7 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA2NM_000742.4 linkc.1568C>T p.Pro523Leu missense_variant Exon 7 of 7 ENST00000407991.3 NP_000733.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CHRNA2ENST00000407991.3 linkc.1568C>T p.Pro523Leu missense_variant Exon 7 of 7 5 NM_000742.4 ENSP00000385026.1

Frequencies

GnomAD3 genomes
AF:
0.0000460
AC:
7
AN:
152242
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000735
Gnomad OTH
AF:
0.000478
GnomAD2 exomes
AF:
0.0000477
AC:
12
AN:
251472
AF XY:
0.0000662
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000867
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.0000544
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000352
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000520
AC:
76
AN:
1461882
Hom.:
0
Cov.:
30
AF XY:
0.0000523
AC XY:
38
AN XY:
727244
show subpopulations
African (AFR)
AF:
0.0000896
AC:
3
AN:
33480
American (AMR)
AF:
0.0000894
AC:
4
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000504
AC:
2
AN:
39700
South Asian (SAS)
AF:
0.000162
AC:
14
AN:
86258
European-Finnish (FIN)
AF:
0.0000187
AC:
1
AN:
53418
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000441
AC:
49
AN:
1112004
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.488
Heterozygous variant carriers
0
5
11
16
22
27
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.0000459
AC:
7
AN:
152360
Hom.:
0
Cov.:
33
AF XY:
0.0000671
AC XY:
5
AN XY:
74504
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41584
American (AMR)
AF:
0.00
AC:
0
AN:
15310
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10620
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000735
AC:
5
AN:
68034
Other (OTH)
AF:
0.000473
AC:
1
AN:
2114
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.504
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000239
Hom.:
0
Bravo
AF:
0.0000831
TwinsUK
AF:
0.00
AC:
0
ALSPAC
AF:
0.000259
AC:
1
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.0000576
AC:
7
Asia WGS
AF:
0.000577
AC:
2
AN:
3478
EpiCase
AF:
0.0000545
EpiControl
AF:
0.0000593

ClinVar

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

Submissions by phenotype

not provided Uncertain:1
Sep 15, 2020
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge; Observed in 0.0048% (12/251472 alleles) in large population cohorts (Lek et al., 2016) -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1
Nov 19, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Inborn genetic diseases Benign:1
Sep 18, 2020
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
Pathogenic
0.83
BayesDel_addAF
Uncertain
0.077
D
BayesDel_noAF
Uncertain
0.070
CADD
Pathogenic
27
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.64
D;.;.
Eigen
Uncertain
0.53
Eigen_PC
Uncertain
0.41
FATHMM_MKL
Pathogenic
0.98
D
LIST_S2
Uncertain
0.87
D;D;D
M_CAP
Uncertain
0.24
D
MetaRNN
Pathogenic
0.81
D;D;D
MetaSVM
Uncertain
0.017
D
MutationAssessor
Uncertain
2.6
M;.;.
PhyloP100
10
PrimateAI
Uncertain
0.73
T
PROVEAN
Pathogenic
-5.3
D;.;D
REVEL
Uncertain
0.56
Sift
Pathogenic
0.0
D;.;D
Sift4G
Pathogenic
0.0010
D;D;D
Polyphen
0.98
D;.;.
Vest4
0.67
MVP
0.79
MPC
0.67
ClinPred
0.84
D
GERP RS
4.9
Varity_R
0.63
gMVP
0.69
Mutation Taster
=42/58
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: rs145238683; hg19: chr8-27319168; COSMIC: COSV99532605; COSMIC: COSV99532605; API