rs143223159

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_StrongBP6_Very_StrongBP7BS2

The NM_000742.4(CHRNA2):​c.1500C>T​(p.Ile500Ile) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000254 in 1,614,156 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0013 ( 1 hom., cov: 33)
Exomes 𝑓: 0.00014 ( 2 hom. )

Consequence

CHRNA2
NM_000742.4 synonymous

Scores

2

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:7

Conservation

PhyloP100: -1.02

Publications

0 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: Benign. The variant received -17 ACMG points.

BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.74).
BP6
Variant 8-27461719-G-A is Benign according to our data. Variant chr8-27461719-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 204950.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
BP7
Synonymous conserved (PhyloP=-1.02 with no splicing effect.
BS2
High AC in GnomAd4 at 205 AD gene.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
CHRNA2NM_000742.4 linkc.1500C>T p.Ile500Ile synonymous_variant Exon 7 of 7 ENST00000407991.3 NP_000733.2 Q15822-1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
CHRNA2ENST00000407991.3 linkc.1500C>T p.Ile500Ile synonymous_variant Exon 7 of 7 5 NM_000742.4 ENSP00000385026.1 Q15822-1

Frequencies

GnomAD3 genomes
AF:
0.00133
AC:
203
AN:
152230
Hom.:
1
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00473
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000327
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:
0.0000294
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000362
AC:
91
AN:
251452
AF XY:
0.000213
show subpopulations
Gnomad AFR exome
AF:
0.00511
Gnomad AMR exome
AF:
0.000173
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000140
AC:
205
AN:
1461808
Hom.:
2
Cov.:
30
AF XY:
0.000107
AC XY:
78
AN XY:
727208
show subpopulations
African (AFR)
AF:
0.00466
AC:
156
AN:
33476
American (AMR)
AF:
0.000268
AC:
12
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53418
Middle Eastern (MID)
AF:
0.000173
AC:
1
AN:
5768
European-Non Finnish (NFE)
AF:
0.00000540
AC:
6
AN:
1111944
Other (OTH)
AF:
0.000497
AC:
30
AN:
60390
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.478
Heterozygous variant carriers
0
11
22
34
45
56
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
10
20
30
40
50
<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:
0.00135
AC:
205
AN:
152348
Hom.:
1
Cov.:
33
AF XY:
0.00126
AC XY:
94
AN XY:
74500
show subpopulations
African (AFR)
AF:
0.00476
AC:
198
AN:
41570
American (AMR)
AF:
0.000327
AC:
5
AN:
15304
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:
4834
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10622
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000294
AC:
2
AN:
68038
Other (OTH)
AF:
0.00
AC:
0
AN:
2114
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.502
Heterozygous variant carriers
0
10
20
29
39
49
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Genome Hom
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
Alfa
AF:
0.000907
Hom.:
1
Bravo
AF:
0.00158

ClinVar

Significance: Benign/Likely benign
Submissions summary: Benign:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not specified Benign:2
Dec 29, 2014
GeneDx
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Jul 19, 2016
Eurofins Ntd Llc (ga)
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

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

- -

Inborn genetic diseases Benign:1
Oct 18, 2016
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. -

not provided Benign:1
Sep 01, 2023
CeGaT Center for Human Genetics Tuebingen
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

CHRNA2: BP4, BP7 -

CHRNA2-related disorder Benign:1
Feb 24, 2019
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 4 Benign:1
Jan 12, 2018
Illumina Laboratory Services, Illumina
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.74
CADD
Benign
6.0
DANN
Benign
0.87
PhyloP100
-1.0
Mutation Taster
=100/0
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.020
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: rs143223159; hg19: chr8-27319236; API