Genetic Variant NM_000744.7:c.729G>A (chr20-63350682-C-T) – ACMG Classification: Benign (-10 pts)

Variant summary

Our verdict is Benign. The variant received -10 ACMG points: 0P and 10B. BP4_StrongBP6BP7BS2

The NM_000744.7(CHRNA4):c.729G>A(p.Pro243Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000539 in 1,613,640 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000051 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:4O:1

Conservation

PhyloP100: -5.42

Publications

3 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 -10 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.78).

BP6

Variant 20-63350682-C-T is Benign according to our data. Variant chr20-63350682-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 98334.

BP7

Synonymous conserved (PhyloP=-5.42 with no splicing effect.

BS2

High AC in GnomAd4 at 12 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.729G>A	p.Pro243Pro	synonymous	Exon 5 of 6	NP_000735.1	P43681-1
CHRNA4	NM_001256573.2		c.201G>A	p.Pro67Pro	synonymous	Exon 5 of 6	NP_001243502.1	Q4VAQ3
CHRNA4	NR_046317.2		n.938G>A		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.729G>A	p.Pro243Pro	synonymous	Exon 5 of 6	ENSP00000359285.4	P43681-1
CHRNA4	ENST00000463705.5	TSL:1	n.1377G>A		non_coding_transcript_exon	Exon 4 of 5
CHRNA4	ENST00000467563.3	TSL:1	n.799G>A		non_coding_transcript_exon	Exon 5 of 6

Frequencies

GnomAD3 genomes

AF:

0.0000790

AC:

AN:

151888

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000968

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000399

AC:

AN:

250774

AF XY:

0.0000516

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000707

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000513

AC:

AN:

1461752

Hom.:

Cov.:

AF XY:

0.0000550

AC XY:

AN XY:

727156

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000756

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.0000188

AC:

AN:

53294

Middle Eastern (MID)

AF:

0.000173

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000603

AC:

AN:

1112002

Other (OTH)

AF:

0.0000166

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.488

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:

0.0000790

AC:

AN:

151888

Hom.:

Cov.:

AF XY:

0.0000539

AC XY:

AN XY:

74174

show subpopulations

African (AFR)

AF:

0.0000968

AC:

AN:

41314

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5180

South Asian (SAS)

AF:

0.00

AC:

AN:

4810

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10590

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

67954

Other (OTH)

AF:

0.00

AC:

AN:

2084

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

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:

0.0000839

Hom.:

Bravo

AF:

0.0000907

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (2)

Autosomal dominant nocturnal frontal lobe epilepsy (1)

CHRNA4-related disorder (1)

not specified (1)

Tobacco use disorder (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.78

CADD

Benign

0.29

(source)

DANN

Benign

0.72

PhyloP100

-5.4

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