rs541282922

chr8-27467331-C-Achr8-27467331-C-T

Variant summary

Our verdict is Benign. Variant got -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS2

The NM_000742.4(CHRNA2):c.347G>T(p.Ser116Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000127 in 1,610,348 control chromosomes in the GnomAD database, including 5 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S116G) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000053 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00014 (5 hom.)
• Consequence: CHRNA2 NM_000742.4 missense
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:3
• Conservation: PhyloP100: -0.376

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]

ACMG classification

Verdict is Benign. Variant got -16 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.050329536).
• BP6: Variant 8-27467331-C-A is Benign according to our data. Variant chr8-27467331-C-A is described in ClinVar as [Likely_benign]. Clinvar id is 204945.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAd at 8 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA2	NM_000742.4	c.347G>T	p.Ser116Ile	missense_variant	5/7	ENST00000407991.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA2	ENST00000407991.3	c.347G>T	p.Ser116Ile	missense_variant	5/7	5	NM_000742.4	P2

Frequencies

GnomAD3 genomes AF: 0.0000526 AC: 8 AN: 152226 Hom.: 0 Cov.: 32

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: 0.00145

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000270 AC: 68 AN: 251448 Hom.: 3 AF XY: 0.000375 AC XY: 51 AN XY: 135902

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000867

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00212

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000135 AC: 197 AN: 1458004 Hom.: 5 Cov.: 30 AF XY: 0.000208 AC XY: 151 AN XY: 725528

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000895

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00212

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.02e-7

Gnomad4 OTH exome AF: 0.0000830

GnomAD4 genome AF: 0.0000525 AC: 8 AN: 152344 Hom.: 0 Cov.: 32 AF XY: 0.0000806 AC XY: 6 AN XY: 74482

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00145

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000136 Hom.: 0

Bravo AF: 0.0000227

ExAC AF: 0.000272 AC: 33

Asia WGS AF: 0.000577 AC: 2 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Aug 02, 2020

- -

not provided Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Dec 21, 2020

- -

CHRNA2-related condition Benign:1

Likely benign, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jul 01, 2019

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.46	T
BayesDel_noAF	Benign	-0.44
Cadd	Benign	6.5
Dann	Benign	0.31
DEOGEN2	Benign	0.36	T;.;.
Eigen	Benign	-1.5
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.083	N
LIST_S2	Benign	0.70	T;T;T
M_CAP	Benign	0.024	T
MetaRNN	Benign	0.050	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-0.17	N;.;.
MutationTaster	Benign	1.0	N;N;N
PrimateAI	Benign	0.43	T
PROVEAN	Benign	-1.9	N;.;N
REVEL	Benign	0.094
Sift	Benign	0.34	T;.;T
Sift4G	Benign	0.54	T;T;T
Polyphen		0.0040	B;.;.
Vest4		0.45
MutPred		0.33		Gain of methylation at K119 (P = 0.0786);.;.;
MVP		0.53
MPC		0.52
ClinPred		0.025	T
GERP RS		-5.6
Varity_R		0.11
gMVP		0.43

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

LitVar

Other links and lift over

dbSNP: rs541282922; hg19: chr8-27324848;