rs147530139

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PP3_ModerateBP6BS2

The NM_000742.4(CHRNA2):c.987C>T(p.Gly329Gly) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000315 in 1,614,090 control chromosomes in the GnomAD database, including 2 homozygotes. 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 0.00050 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00030 ( 2 hom. )

Consequence

CHRNA2
NM_000742.4 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: -0.280

Publications

2 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

CHRNA2 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

BP6

Variant 8-27463456-G-A is Benign according to our data. Variant chr8-27463456-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 204990.

BS2

High AC in GnomAd4 at 76 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA2	NM_000742.4 link	c.987C>T	p.Gly329Gly	synonymous_variant	Exon 6 of 7	ENST00000407991.3	NP_000733.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA2	ENST00000407991.3 link	c.987C>T	p.Gly329Gly	synonymous_variant	Exon 6 of 7	5	NM_000742.4	ENSP00000385026.1

Frequencies

GnomAD3 genomes

AF:

0.000499

AC:

AN:

152218

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00602

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000132

Gnomad OTH

AF:

0.000955

GnomAD2 exomes

AF:

0.000597

AC:

150

AN:

251396

AF XY:

0.000545

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00532

Gnomad NFE exome

AF:

0.000193

Gnomad OTH exome

AF:

0.00147

GnomAD4 exome

AF:

0.000296

AC:

433

AN:

1461872

Hom.:

Cov.:

AF XY:

0.000278

AC XY:

202

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.0000894

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:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00670

AC:

358

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000468

AC:

AN:

1112012

Other (OTH)

AF:

0.000315

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.489

Heterozygous variant carriers

109

145

181

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:

0.000499

AC:

AN:

152218

Hom.:

Cov.:

AF XY:

0.000740

AC XY:

AN XY:

74366

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41456

American (AMR)

AF:

0.00

AC:

AN:

15278

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.000207

AC:

AN:

4832

European-Finnish (FIN)

AF:

0.00602

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000132

AC:

AN:

68040

Other (OTH)

AF:

0.000955

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.499

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:

0.000199

Hom.:

Bravo

AF:

0.0000378

EpiCase

AF:

0.0000545

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jun 26, 2014

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

p.Gly329Gly (G329G) GGC>GGT: c.987 C>T in exon 6 of the CHRNA2 gene (NM_000742.3). The c.987 C>T variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. The c.987 C>T variant was not observed with any significant frequency in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project. Multiple in silico algorithms predict that c.987 C>T could potentially create a cryptic donor site in exon 6 that may supplant the natural donor site. However, to our knowledge, no splice mutations have been reported in the CHRNA2 gene, and in the absence of RNA/functional studies, the actual effect of c.987 C>T is unknown. The variant is found in EPILEPSY panel(s). -

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Oct 30, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.54

CADD

Benign

(source)

DANN

Benign

0.88

PhyloP100

-0.28

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.93

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.93

Position offset: 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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over