rs751699392

Positions:

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 2P and 12B. PP3_ModerateBP6_Very_StrongBS2

The NM_000742.4(CHRNA2):c.1099C>T(p.Arg367Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000242 in 1,613,778 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 Likely benign (★★).

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

CHRNA2
NM_000742.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4

Conservation

PhyloP100: 1.46

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -10 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.935

BP6

Variant 8-27463344-G-A is Benign according to our data. Variant chr8-27463344-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 362695.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BS2

High AC in GnomAd4 at 10 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNA2	NM_000742.4 linkuse as main transcript	c.1099C>T	p.Arg367Trp	missense_variant	6/7	ENST00000407991.3	NP_000733.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNA2	ENST00000407991.3 linkuse as main transcript	c.1099C>T	p.Arg367Trp	missense_variant	6/7	5	NM_000742.4	ENSP00000385026	P2	Q15822-1

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152176

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000524

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

GnomAD3 exomes

AF:

0.0000762

AC:

AN:

249216

Hom.:

AF XY:

0.0000519

AC XY:

AN XY:

134876

show subpopulations

Gnomad AFR exome

AF:

0.0000622

Gnomad AMR exome

AF:

0.000318

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000139

Gnomad NFE exome

AF:

0.00000893

Gnomad OTH exome

AF:

0.000329

GnomAD4 exome

AF:

0.0000198

AC:

AN:

1461602

Hom.:

Cov.:

AF XY:

0.0000193

AC XY:

AN XY:

727066

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.000380

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.0000188

Gnomad4 NFE exome

AF:

0.00000630

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152176

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74350

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.000524

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.0000907

ExAC

AF:

0.0000494

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Oct 01, 2024

Variant summary: CHRNA2 c.1099C>T (p.Arg367Trp) results in a non-conservative amino acid change located in the Neurotransmitter-gated ion-channel transmembrane domain (IPR006029) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 7.6e-05 in 249216 control chromosomes, predominantly at a frequency of 0.00032 within the Latino subpopulation in the gnomAD database. This frequency is not significantly higher than estimated for a pathogenic variant in CHRNA2 causing Autosomal Dominant Nocturnal Frontal Lobe Epilepsy 4, allowing no conclusion about variant significance. To our knowledge, no occurrence of c.1099C>T in individuals affected with Autosomal Dominant Nocturnal Frontal Lobe Epilepsy 4 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 362695). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 10, 2024

- -

Inborn genetic diseases

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 13, 2021

This alteration is classified as 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

Likely benign, criteria provided, single submitter

clinical testing

GeneDx

Feb 11, 2019

- -

Autosomal dominant nocturnal frontal lobe epilepsy 4

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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

AlphaMissense

Benign

0.18

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.15

CADD

Benign

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.93

D;.;.

Eigen

Benign

0.13

Eigen_PC

Benign

-0.14

FATHMM_MKL

Benign

0.67

LIST_S2

Uncertain

0.94

D;D;D

M_CAP

Uncertain

0.086

MetaRNN

Pathogenic

0.94

D;D;D

MetaSVM

Uncertain

0.69

MutationAssessor

Pathogenic

4.5

H;.;.

MutationTaster

Benign

0.85

D;D;D

PrimateAI

Benign

0.44

PROVEAN

Pathogenic

-6.4

D;.;D

REVEL

Uncertain

0.51

Sift

Pathogenic

0.0

D;.;D

Sift4G

Pathogenic

0.0

D;D;D

Polyphen

1.0

D;.;.

Vest4

0.72

MVP

0.88

MPC

0.72

ClinPred

0.98

GERP RS

-0.77

Varity_R

0.69

gMVP

0.74

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over