Genetic Variant NM_000742.4:c.489C>T (chr8-27463954-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_000742.4(CHRNA2):c.489C>T(p.Ala163Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000852 in 1,614,172 control chromosomes in the GnomAD database, including 14 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00045 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00089 ( 14 hom. )

Consequence

CHRNA2
NM_000742.4 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.723

Publications

1 publications found

Variant links:

Genes affected

CHRNA2 (HGNC:1956): (cholinergic receptor nicotinic alpha 2 subunit) Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels formed by a pentameric arrangement of alpha and beta subunits to create distinct muscle and neuronal receptors. Neuronal receptors are found throughout the peripheral and central nervous system where they are involved in fast synaptic transmission. This gene encodes an alpha subunit that is widely expressed in the brain. The proposed structure for nAChR subunits is a conserved N-terminal extracellular domain followed by three conserved transmembrane domains, a variable cytoplasmic loop, a fourth conserved transmembrane domain, and a short C-terminal extracellular region. Mutations in this gene cause autosomal dominant nocturnal frontal lobe epilepsy type 4. Single nucleotide polymorphisms (SNPs) in this gene have been associated with nicotine dependence. [provided by RefSeq, Nov 2009]

CHRNA2 Gene-Disease associations (from GenCC):

autosomal dominant nocturnal frontal lobe epilepsy 4
Inheritance: AD Classification: STRONG, LIMITED Submitted by: G2P, Illumina, Labcorp Genetics (formerly Invitae)
autosomal dominant nocturnal frontal lobe epilepsy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
familial sleep-related hypermotor epilepsy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
benign familial infantile epilepsy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
epilepsy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

CHRNA2 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=-0.58).

BP6

Variant 8-27463954-G-A is Benign according to our data. Variant chr8-27463954-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 136750.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-0.723 with no splicing effect.

BS2

High AC in GnomAd4 at 69 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000742.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CHRNA2	NM_000742.4	MANE Select	c.489C>T	p.Ala163Ala	synonymous	Exon 6 of 7	NP_000733.2	Q15822-1
CHRNA2	NM_001282455.2		c.444C>T	p.Ala148Ala	synonymous	Exon 6 of 7	NP_001269384.1	Q15822-2
CHRNA2	NM_001347705.2		c.12C>T	p.Ala4Ala	synonymous	Exon 6 of 7	NP_001334634.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
CHRNA2	ENST00000407991.3	TSL:5 MANE Select	c.489C>T	p.Ala163Ala	synonymous	Exon 6 of 7	ENSP00000385026.1	Q15822-1
CHRNA2	ENST00000520600.1	TSL:1	n.290-2200C>T		intron	N/A
CHRNA2	ENST00000523695.5	TSL:1	n.450-94C>T		intron	N/A	ENSP00000430612.1	E5RJ54

Frequencies

GnomAD3 genomes

AF:

0.000447

AC:

AN:

152164

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.0135

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00184

AC:

463

AN:

251400

AF XY:

0.00238

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.0000289

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.000652

GnomAD4 exome

AF:

0.000893

AC:

1306

AN:

1461890

Hom.:

Cov.:

AF XY:

0.00130

AC XY:

943

AN XY:

727244

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0144

AC:

1244

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000126

AC:

AN:

1112012

Other (OTH)

AF:

0.000778

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.487

Heterozygous variant carriers

102

204

306

408

510

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:

0.000453

AC:

AN:

152282

Hom.:

Cov.:

AF XY:

0.000806

AC XY:

AN XY:

74464

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41562

American (AMR)

AF:

0.0000654

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.0137

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

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:

0.000128

Hom.:

Bravo

AF:

0.0000756

Asia WGS

AF:

0.00664

AC:

AN:

3478

ClinVar

ClinVar submissions

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)

Autosomal dominant nocturnal frontal lobe epilepsy 4 (1)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.58

CADD

Benign

6.2

(source)

DANN

Benign

0.82

PhyloP100

-0.72

Mutation Taster

=98/2

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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