chr20-63349802-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_ModerateBP6BS2

The NM_000744.7(CHRNA4):c.1609C>T(p.Pro537Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000151 in 1,453,614 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 0.000015 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.83

Publications

2 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

CHRNA4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -7 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.106532186).

BP6

Variant 20-63349802-G-A is Benign according to our data. Variant chr20-63349802-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 393180.

BS2

High AC in GnomAdExome4 at 22 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA4	NM_000744.7 link	c.1609C>T	p.Pro537Ser	missense_variant	Exon 5 of 6	ENST00000370263.9	NP_000735.1	P43681-1B4DK78Q59FV0
CHRNA4	NM_001256573.2 link	c.1081C>T	p.Pro361Ser	missense_variant	Exon 5 of 6		NP_001243502.1	P43681Q4VAQ3B4DK78Q59FV0
CHRNA4	NR_046317.2 link	n.1818C>T		non_coding_transcript_exon_variant	Exon 5 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 link	c.1609C>T	p.Pro537Ser	missense_variant	Exon 5 of 6	1	NM_000744.7	ENSP00000359285.4		P43681-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.0000649

AC:

AN:

246464

AF XY:

0.0000299

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000466

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000151

AC:

AN:

1453614

Hom.:

Cov.:

AF XY:

0.00000831

AC XY:

AN XY:

721590

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33270

American (AMR)

AF:

0.000450

AC:

AN:

44478

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25962

East Asian (EAS)

AF:

0.00

AC:

AN:

39464

South Asian (SAS)

AF:

0.00

AC:

AN:

86018

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52098

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5748

European-Non Finnish (NFE)

AF:

0.00000181

AC:

AN:

1106624

Other (OTH)

AF:

0.00

AC:

AN:

59952

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.498

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<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

Cov.:

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000151

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jan 23, 2017

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 P537S variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. The P537S 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 P537S 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. However, this substitution occurs at a position that is not conserved and in silico analysis predicts this variant likely does not alter the protein structure/function. Additionally, 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. -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Oct 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.074

BayesDel_addAF

Benign

-0.30

BayesDel_noAF

Benign

-0.35

CADD

Benign

(source)

DANN

Benign

0.91

DEOGEN2

Benign

0.32

T;.

Eigen

Benign

-0.67

Eigen_PC

Benign

-0.67

FATHMM_MKL

Benign

0.16

LIST_S2

Benign

0.71

T;T

M_CAP

Uncertain

0.16

MetaRNN

Benign

0.11

T;T

MetaSVM

Benign

-0.85

MutationAssessor

Benign

1.4

L;.

PhyloP100

1.8

PrimateAI

Benign

0.33

PROVEAN

Benign

-0.70

N;.

REVEL

Benign

0.15

Sift

Benign

0.14

T;.

Sift4G

Benign

0.54

T;T

Polyphen

0.27

B;.

Vest4

0.18

MutPred

0.31

Gain of phosphorylation at P537 (P = 0.0184);.;

MVP

0.82

MPC

0.72

ClinPred

0.036

GERP RS

2.5

Varity_R

0.037

gMVP

0.27

Mutation Taster

=97/3

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over