rs371858399

chr8-27463459-G-A

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_Strong BP6 BP7 BS2

The NM_000742.4(CHRNA2):c.984C>T(p.Ile328=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000026 in 1,614,180 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 0.000092 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000019 (0 hom.)
• Consequence: CHRNA2 NM_000742.4 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: -0.631

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 -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.59).
• BP6: Variant 8-27463459-G-A is Benign according to our data. Variant chr8-27463459-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 476996.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=1, Likely_benign=1}.
• BP7: Synonymous conserved (PhyloP=-0.631 with no splicing effect.
• BS2: High AC in GnomAd at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA2	NM_000742.4	c.984C>T	p.Ile328=	synonymous_variant	6/7	ENST00000407991.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA2	ENST00000407991.3	c.984C>T	p.Ile328=	synonymous_variant	6/7	5	NM_000742.4	P2

Frequencies

GnomAD3 genomes AF: 0.0000920 AC: 14 AN: 152186 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000385

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.0000756 AC: 19 AN: 251396 Hom.: 0 AF XY: 0.0000810 AC XY: 11 AN XY: 135886

Gnomad AFR exome AF: 0.000246

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000652

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000264

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000192 AC: 28 AN: 1461876 Hom.: 0 Cov.: 33 AF XY: 0.0000248 AC XY: 18 AN XY: 727242

Gnomad4 AFR exome AF: 0.000239

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000202

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000809

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000919 AC: 14 AN: 152304 Hom.: 0 Cov.: 33 AF XY: 0.000121 AC XY: 9 AN XY: 74472

Gnomad4 AFR AF: 0.000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000386

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.000473

Alfa AF: 0.0000772 Hom.: 0

Bravo AF: 0.000132

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Jan 04, 2017

- -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Oct 16, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.59
Cadd	Benign	9.3
Dann	Benign	0.89

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

LitVar

Other links and lift over

dbSNP: rs371858399; hg19: chr8-27320976; COSMIC: COSV53556799; COSMIC: COSV53556799;