rs375340441

Positions:

chr20-63350450-T-C

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP3BP6BS1BS2

The ENST00000370263.9(CHRNA4):c.961A>G(p.Ile321Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000496 in 1,613,262 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). Synonymous variant affecting the same amino acid position (i.e. I321I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

CHRNA4
ENST00000370263.9 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 6.07

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -8 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.746

BP6

Variant 20-63350450-T-C is Benign according to our data. Variant chr20-63350450-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 421774.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

BS1

Variant frequency is greater than expected in population afr. gnomad4_exome allele frequency = 0.00000342 (5/1461668) while in subpopulation AFR AF= 0.000119 (4/33480). AF 95% confidence interval is 0.0000398. There are 0 homozygotes in gnomad4_exome. There are 3 alleles in male gnomad4_exome subpopulation. Median coverage is 99. This position pass quality control queck.

BS2

High AC in GnomAdExome4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein
CHRNA4	NM_000744.7 linkuse as main transcript	c.961A>G	p.Ile321Val	missense_variant	5/6	ENST00000370263.9	NP_000735.1
CHRNA4	NM_001256573.2 linkuse as main transcript	c.433A>G	p.Ile145Val	missense_variant	5/6		NP_001243502.1
CHRNA4	NR_046317.2 linkuse as main transcript	n.1170A>G		non_coding_transcript_exon_variant	5/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 linkuse as main transcript	c.961A>G	p.Ile321Val	missense_variant	5/6	1	NM_000744.7	ENSP00000359285	P1	P43681-1

Frequencies

GnomAD3 genomes

AF:

0.0000198

AC:

AN:

151594

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000728

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00000399

AC:

AN:

250932

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135864

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461668

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727118

show subpopulations

Gnomad4 AFR exome

AF:

0.000119

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000198

AC:

AN:

151594

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

73974

show subpopulations

Gnomad4 AFR

AF:

0.0000728

Gnomad4 AMR

AF:

0.00

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:

0.0000329

Hom.:

Bravo

AF:

0.0000340

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 20, 2024

The c.961A>G (p.I321V) alteration is located in exon 5 (coding exon 5) of the CHRNA4 gene. This alteration results from a A to G substitution at nucleotide position 961, causing the isoleucine (I) at amino acid position 321 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 25, 2019

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports that this variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 16, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Uncertain

0.099

BayesDel_noAF

Uncertain

0.090

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Benign

0.33

T;.

Eigen

Uncertain

0.48

Eigen_PC

Uncertain

0.54

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.88

D;D

M_CAP

Uncertain

0.15

MetaRNN

Pathogenic

0.75

D;D

MetaSVM

Uncertain

0.34

MutationAssessor

Benign

1.9

L;.

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.70

PROVEAN

Benign

-1.0

N;.

REVEL

Pathogenic

0.66

Sift

Benign

0.13

T;.

Sift4G

Uncertain

0.030

D;D

Polyphen

0.62

P;.

Vest4

0.76

MVP

0.91

MPC

1.1

ClinPred

0.75

GERP RS

5.2

Varity_R

0.19

gMVP

0.47

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