Genetic Variant CHRNA4:p.His453His (chr20-63350052-G-A) – 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.1359C>T(p.His453His) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000311 in 1,512,986 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000026 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:2O:1

Conservation

PhyloP100: -0.644

Publications

4 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: G2P, Labcorp Genetics (formerly Invitae)
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=-0.87).

BP6

Variant 20-63350052-G-A is Benign according to our data. Variant chr20-63350052-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 98314.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-0.644 with no splicing effect.

BS2

High AC in GnomAd4 at 11 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	UniProt
CHRNA4	NM_000744.7	MANE Select	c.1359C>T	p.His453His	synonymous	Exon 5 of 6	NP_000735.1	P43681-1
CHRNA4	NM_001256573.2		c.831C>T	p.His277His	synonymous	Exon 5 of 6	NP_001243502.1	Q4VAQ3
CHRNA4	NR_046317.2		n.1568C>T		non_coding_transcript_exon	Exon 5 of 6

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CHRNA4	ENST00000370263.9	TSL:1 MANE Select	c.1359C>T	p.His453His	synonymous	Exon 5 of 6	ENSP00000359285.4	P43681-1
CHRNA4	ENST00000463705.5	TSL:1	n.2007C>T		non_coding_transcript_exon	Exon 4 of 5
CHRNA4	ENST00000467563.3	TSL:1	n.1429C>T		non_coding_transcript_exon	Exon 5 of 6

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152224

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000241

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000972

AC:

AN:

133682

AF XY:

0.000127

show subpopulations

Gnomad AFR exome

AF:

0.000223

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000193

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000265

AC:

AN:

1360762

Hom.:

Cov.:

AF XY:

0.0000255

AC XY:

AN XY:

665880

show subpopulations

African (AFR)

AF:

0.000161

AC:

AN:

30984

American (AMR)

AF:

0.00

AC:

AN:

31862

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

21436

East Asian (EAS)

AF:

0.00

AC:

AN:

37214

South Asian (SAS)

AF:

0.00

AC:

AN:

71146

European-Finnish (FIN)

AF:

0.00

AC:

AN:

45260

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5138

European-Non Finnish (NFE)

AF:

0.0000292

AC:

AN:

1061648

Other (OTH)

AF:

0.00

AC:

AN:

56074

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

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

AF:

0.0000723

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74364

show subpopulations

African (AFR)

AF:

0.000241

AC:

AN:

41466

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4836

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68024

Other (OTH)

AF:

0.00

AC:

AN:

2092

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

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:

0.00

Hom.:

Bravo

AF:

0.0000869

ClinVar

ClinVar submissions

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Autosomal dominant nocturnal frontal lobe epilepsy (1)

not specified (1)

Tobacco use disorder (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.87

CADD

Benign

2.3

(source)

DANN

Benign

0.40

PhyloP100

-0.64

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