Genetic Variant CHRNA2:n.1017T>G (chr8-27461027-A-C) – ACMG Classification: Likely_benign (-2 pts)

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2BP4_Strong

The ENST00000520600.1(CHRNA2):n.1017T>G variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 30)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

CHRNA2
ENST00000520600.1 non_coding_transcript_exon

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -3.68

Publications

8 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:

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ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.96).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNA2	NM_000742.4 link	c.*602T>G		3_prime_UTR_variant	Exon 7 of 7	ENST00000407991.3	NP_000733.2	Q15822-1

Ensembl

Gene	Transcript	HGVSc	Effect	Exon rank	TSL	MANE	Protein	UniProt
CHRNA2	ENST00000520600.1 link	n.1017T>G	non_coding_transcript_exon_variant	Exon 2 of 2	1
CHRNA2	ENST00000407991.3 link	c.*602T>G	3_prime_UTR_variant	Exon 7 of 7	5	NM_000742.4	ENSP00000385026.1	Q15822-1
CHRNA2	ENST00000523695.5 link	n.*1594T>G	downstream_gene_variant		1		ENSP00000430612.1	E5RJ54
CHRNA2	ENST00000520933.7 link	c.*602T>G	downstream_gene_variant		5		ENSP00000429616.2	A0A0X1KG79

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

2394

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

1450

African (AFR)

AF:

0.00

AC:

AN:

American (AMR)

AF:

0.00

AC:

AN:

346

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

East Asian (EAS)

AF:

0.00

AC:

AN:

South Asian (SAS)

AF:

0.00

AC:

AN:

138

European-Finnish (FIN)

AF:

0.00

AC:

AN:

Middle Eastern (MID)

AF:

0.00

AC:

AN:

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1648

Other (OTH)

AF:

0.00

AC:

AN:

102

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.96

CADD

Benign

0.097

(source)

DANN

Benign

0.79

PhyloP100

-3.7

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

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over