dbSNP rs201488442: CHRNA4:p.Ala134Ala (chr20-63351009-C-T) – ACMG Classification: Benign (-17 pts)

Variant summary

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

The NM_000744.7(CHRNA4):c.402G>A(p.Ala134Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000516 in 1,613,130 control chromosomes in the GnomAD database, including 12 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00048 ( 2 hom., cov: 32)

Exomes 𝑓: 0.00052 ( 10 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:5

Conservation

PhyloP100: -5.29

Publications

1 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 -17 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.89).

BP6

Variant 20-63351009-C-T is Benign according to our data. Variant chr20-63351009-C-T is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 136756.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-5.28 with no splicing effect.

BS2

High AC in GnomAd4 at 73 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000744.7. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CHRNA4	NM_000744.7	MANE Select	c.402G>A	p.Ala134Ala	synonymous	Exon 5 of 6	NP_000735.1
CHRNA4	NM_001256573.2		c.-127G>A		5_prime_UTR	Exon 5 of 6	NP_001243502.1
CHRNA4	NR_046317.2		n.611G>A		non_coding_transcript_exon	Exon 5 of 6

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CHRNA4	ENST00000370263.9	TSL:1 MANE Select	c.402G>A	p.Ala134Ala	synonymous	Exon 5 of 6	ENSP00000359285.4
CHRNA4	ENST00000463705.5	TSL:1	n.1050G>A		non_coding_transcript_exon	Exon 4 of 5
CHRNA4	ENST00000467563.3	TSL:1	n.472G>A		non_coding_transcript_exon	Exon 5 of 6

Frequencies

GnomAD3 genomes

AF:

0.000481

AC:

AN:

151920

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000726

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00154

Gnomad SAS

AF:

0.0116

Gnomad FIN

AF:

0.000283

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00113

AC:

283

AN:

249416

AF XY:

0.00147

show subpopulations

Gnomad AFR exome

AF:

0.0000621

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00218

Gnomad FIN exome

AF:

0.000514

Gnomad NFE exome

AF:

0.0000445

Gnomad OTH exome

AF:

0.000820

GnomAD4 exome

AF:

0.000519

AC:

759

AN:

1461092

Hom.:

Cov.:

AF XY:

0.000726

AC XY:

528

AN XY:

726782

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33476

American (AMR)

AF:

0.0000447

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.000957

AC:

AN:

39698

South Asian (SAS)

AF:

0.00699

AC:

603

AN:

86250

European-Finnish (FIN)

AF:

0.000474

AC:

AN:

52712

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000297

AC:

AN:

1111962

Other (OTH)

AF:

0.000927

AC:

AN:

60380

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

Heterozygous variant carriers

126

189

252

315

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.000480

AC:

AN:

152038

Hom.:

Cov.:

AF XY:

0.000673

AC XY:

AN XY:

74284

show subpopulations

African (AFR)

AF:

0.0000724

AC:

AN:

41448

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3466

East Asian (EAS)

AF:

0.00154

AC:

AN:

5178

South Asian (SAS)

AF:

0.0116

AC:

AN:

4808

European-Finnish (FIN)

AF:

0.000283

AC:

AN:

10590

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000441

AC:

AN:

67966

Other (OTH)

AF:

0.00

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.482

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

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

Alfa

AF:

0.000128

Hom.:

Bravo

AF:

0.000117

Asia WGS

AF:

0.00433

AC:

AN:

3478

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions as Germline

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not specified (2)

Autosomal dominant nocturnal frontal lobe epilepsy (1)

Inborn genetic diseases (1)

not provided (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.89

CADD

Benign

0.053

(source)

DANN

Benign

0.85

PhyloP100

-5.3

Mutation Taster

=99/1

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over