rs121912274

Variant names:

Variant summary

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

The NM_000744.7(CHRNA4):c.1266C>T(p.Cys422Cys) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000394 in 1,573,308 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 0.000053 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000038 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: 1.96

Publications

1 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 -10 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.71).

BP6

Variant 20-63350145-G-A is Benign according to our data. Variant chr20-63350145-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 98312.

BP7

Synonymous conserved (PhyloP=1.96 with no splicing effect.

BS2

High AC in GnomAd4 at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein
CHRNA4	NM_000744.7 link	c.1266C>T	p.Cys422Cys	synonymous_variant	Exon 5 of 6	ENST00000370263.9	NP_000735.1
CHRNA4	NM_001256573.2 link	c.738C>T	p.Cys246Cys	synonymous_variant	Exon 5 of 6		NP_001243502.1
CHRNA4	NR_046317.2 link	n.1475C>T		non_coding_transcript_exon_variant	Exon 5 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNA4	ENST00000370263.9 link	c.1266C>T	p.Cys422Cys	synonymous_variant	Exon 5 of 6	1	NM_000744.7	ENSP00000359285.4

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.0000882

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000251

AC:

AN:

198894

AF XY:

0.0000372

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000584

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000380

AC:

AN:

1421104

Hom.:

Cov.:

AF XY:

0.0000456

AC XY:

AN XY:

701656

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32764

American (AMR)

AF:

0.00

AC:

AN:

40146

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

24828

East Asian (EAS)

AF:

0.00

AC:

AN:

38204

South Asian (SAS)

AF:

0.00

AC:

AN:

81772

European-Finnish (FIN)

AF:

0.00

AC:

AN:

49982

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5650

European-Non Finnish (NFE)

AF:

0.0000487

AC:

AN:

1089136

Other (OTH)

AF:

0.0000171

AC:

AN:

58622

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

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:

0.0000526

AC:

AN:

152204

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74360

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41446

American (AMR)

AF:

0.00

AC:

AN:

15292

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5192

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000882

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.444

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:

0.0000571

Hom.:

Bravo

AF:

0.0000491

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:1Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Jan 14, 2014

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.1266 C>T splice site variant in the CHRNA4 gene has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,400 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Multiple in silico algorithms predict that the c.1266 C>T substitution could potentially introduce a new cryptic donor site that may supplant the natural site in exon 5 and lead to abnormal splicing. However, in the absence of RNA/Functional studies the actual effect of the c.1266 C>T sequence change is unknown. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant as mutations in CHRNA4 demonstrate incomplete penetrance (Hirose and Kurahashi, 2012). This variant has been observed to be maternally inherited. The variant is found in CHILD-EPI panel(s).

Autosomal dominant nocturnal frontal lobe epilepsy

Benign:1

Oct 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Tobacco use disorder

Other:1

Psychiatry Genetics Yale University

Significance:not provided

Review Status:no classification provided

Collection Method:literature only

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.71

CADD

Benign

3.0

(source)

DANN

Benign

0.30

PhyloP100

2.0

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over