Genetic Variant NM_000744.7:c.225C>T (chr20-63359551-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.225C>T(p.Asp75Asp) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00018 in 1,612,656 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 0.00048 ( 0 hom., cov: 34)

Exomes 𝑓: 0.00015 ( 0 hom. )

Consequence

CHRNA4
NM_000744.7 synonymous

Scores

Clinical Significance

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

Conservation

PhyloP100: -1.15

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 -17 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.49).

BP6

Variant 20-63359551-G-A is Benign according to our data. Variant chr20-63359551-G-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 377669.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-1.15 with no splicing effect.

BS2

High AC in GnomAd4 at 73 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
CHRNA4	NM_000744.7	MANE Select	c.225C>T	p.Asp75Asp	synonymous	Exon 2 of 6	NP_000735.1
CHRNA4	NM_001256573.2		c.-322C>T		5_prime_UTR_premature_start_codon_gain	Exon 2 of 6	NP_001243502.1
CHRNA4	NM_001256573.2		c.-322C>T		5_prime_UTR	Exon 2 of 6	NP_001243502.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
CHRNA4	ENST00000370263.9	TSL:1 MANE Select	c.225C>T	p.Asp75Asp	synonymous	Exon 2 of 6	ENSP00000359285.4
CHRNA4	ENST00000467563.3	TSL:1	n.277C>T		non_coding_transcript_exon	Exon 2 of 6
CHRNA4	ENST00000627000.1	TSL:1	n.225C>T		non_coding_transcript_exon	Exon 2 of 6	ENSP00000486914.1

Frequencies

GnomAD3 genomes

AF:

0.000466

AC:

AN:

152222

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.000235

Gnomad OTH

AF:

0.000958

GnomAD2 exomes

AF:

0.000164

AC:

AN:

249774

AF XY:

0.000147

show subpopulations

Gnomad AFR exome

AF:

0.000808

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000222

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000149

AC:

218

AN:

1460316

Hom.:

Cov.:

AF XY:

0.000157

AC XY:

114

AN XY:

726446

show subpopulations

African (AFR)

AF:

0.00105

AC:

AN:

33478

American (AMR)

AF:

0.0000894

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52060

Middle Eastern (MID)

AF:

0.000694

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.000148

AC:

164

AN:

1111862

Other (OTH)

AF:

0.000149

AC:

AN:

60360

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:

0.000479

AC:

AN:

152340

Hom.:

Cov.:

AF XY:

0.000483

AC XY:

AN XY:

74500

show subpopulations

African (AFR)

AF:

0.00125

AC:

AN:

41572

American (AMR)

AF:

0.000196

AC:

AN:

15310

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5182

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000235

AC:

AN:

68038

Other (OTH)

AF:

0.000948

AC:

AN:

2110

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

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:

0.000484

Hom.:

Bravo

AF:

0.000427

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000382

EpiControl

AF:

0.000533

ClinVar

ClinVar submissions as Germline

Significance:Benign/Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (3)

Autosomal dominant nocturnal frontal lobe epilepsy (1)

Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.49

CADD

Benign

1.3

(source)

DANN

Benign

0.90

PhyloP100

-1.1

Mutation Taster

=100/0

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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