dbSNP rs76270730: CHRNA4:p.Phe326Phe (chr20-63350433-G-A) – ACMG Classification: Benign (-15 pts)

Variant summary

Our verdict is Benign. The variant received -15 ACMG points: 0P and 15B. BP4_ModerateBP6_Very_StrongBP7BS2

The NM_000744.7(CHRNA4):c.978C>T(p.Phe326Phe) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00139 in 1,613,930 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0012 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0014 ( 5 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: 0.303

Publications

5 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 -15 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.44).

BP6

Variant 20-63350433-G-A is Benign according to our data. Variant chr20-63350433-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 136757.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.303 with no splicing effect.

BS2

High AC in GnomAd4 at 184 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.978C>T	p.Phe326Phe	synonymous	Exon 5 of 6	NP_000735.1
CHRNA4	NM_001256573.2		c.450C>T	p.Phe150Phe	synonymous	Exon 5 of 6	NP_001243502.1
CHRNA4	NR_046317.2		n.1187C>T		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.978C>T	p.Phe326Phe	synonymous	Exon 5 of 6	ENSP00000359285.4
CHRNA4	ENST00000463705.5	TSL:1	n.1626C>T		non_coding_transcript_exon	Exon 4 of 5
CHRNA4	ENST00000467563.3	TSL:1	n.1048C>T		non_coding_transcript_exon	Exon 5 of 6

Frequencies

GnomAD3 genomes

AF:

0.00121

AC:

184

AN:

152158

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.00173

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00124

Gnomad FIN

AF:

0.00207

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00203

Gnomad OTH

AF:

0.000961

GnomAD2 exomes

AF:

0.00137

AC:

344

AN:

250872

AF XY:

0.00139

show subpopulations

Gnomad AFR exome

AF:

0.0000617

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00169

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00217

Gnomad NFE exome

AF:

0.00194

Gnomad OTH exome

AF:

0.000490

GnomAD4 exome

AF:

0.00141

AC:

2057

AN:

1461654

Hom.:

Cov.:

AF XY:

0.00152

AC XY:

1105

AN XY:

727120

show subpopulations

African (AFR)

AF:

0.000418

AC:

AN:

33480

American (AMR)

AF:

0.000157

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00157

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00168

AC:

145

AN:

86258

European-Finnish (FIN)

AF:

0.00216

AC:

115

AN:

53186

Middle Eastern (MID)

AF:

0.000693

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00151

AC:

1679

AN:

1112008

Other (OTH)

AF:

0.000861

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

Heterozygous variant carriers

163

326

489

652

815

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

104

156

208

260

<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:

0.00121

AC:

184

AN:

152276

Hom.:

Cov.:

AF XY:

0.00125

AC XY:

AN XY:

74456

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41538

American (AMR)

AF:

0.000261

AC:

AN:

15300

Ashkenazi Jewish (ASJ)

AF:

0.00173

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5178

South Asian (SAS)

AF:

0.00124

AC:

AN:

4830

European-Finnish (FIN)

AF:

0.00207

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00203

AC:

138

AN:

68024

Other (OTH)

AF:

0.000951

AC:

AN:

2104

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

Alfa

AF:

0.00136

Hom.:

Bravo

AF:

0.000748

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.00185

EpiControl

AF:

0.00148

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 (3)

not provided (2)

Autosomal dominant nocturnal frontal lobe epilepsy (1)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.44

CADD

Benign

7.3

(source)

DANN

Benign

0.79

PhyloP100

0.30

Mutation Taster

=89/11

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over