rs121912276

chr20-63350052-G-A

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_000744.7(CHRNA4):c.1359C>T(p.His453=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000311 in 1,512,986 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 0.000072 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000026 (0 hom.)
• Consequence: CHRNA4 NM_000744.7 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:2 O:1
• Conservation: PhyloP100: -0.644

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]

ACMG classification

Verdict is Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.87).
• BP6: Variant 20-63350052-G-A is Benign according to our data. Variant chr20-63350052-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 98314.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.644 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0000723 (11/152224) while in subpopulation AFR AF= 0.000241 (10/41466). AF 95% confidence interval is 0.00013. There are 0 homozygotes in gnomad4. There are 6 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
• BS2: High AC in GnomAd at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNA4	NM_000744.7	c.1359C>T	p.His453=	synonymous_variant	5/6	ENST00000370263.9
CHRNA4	NM_001256573.2	c.831C>T	p.His277=	synonymous_variant	5/6
CHRNA4	NR_046317.2	n.1568C>T		non_coding_transcript_exon_variant	5/6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNA4	ENST00000370263.9	c.1359C>T	p.His453=	synonymous_variant	5/6	1	NM_000744.7	P1

Frequencies

GnomAD3 genomes AF: 0.0000723 AC: 11 AN: 152224 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: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000972 AC: 13 AN: 133682 Hom.: 0 AF XY: 0.000127 AC XY: 9 AN XY: 70880

Gnomad AFR exome AF: 0.000223

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000193

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000265 AC: 36 AN: 1360762 Hom.: 0 Cov.: 83 AF XY: 0.0000255 AC XY: 17 AN XY: 665880

Gnomad4 AFR exome AF: 0.000161

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000292

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000723 AC: 11 AN: 152224 Hom.: 0 Cov.: 33 AF XY: 0.0000807 AC XY: 6 AN XY: 74364

Gnomad4 AFR AF: 0.000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000869

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:2 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Benign, criteria provided, single submitter

clinical testing

GeneDx

Oct 23, 2013

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Autosomal dominant nocturnal frontal lobe epilepsy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Sep 22, 2023

- -

Tobacco use disorder Other:1

not provided, no classification provided

literature only

Psychiatry Genetics Yale University

-

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
Cadd	Benign	2.3
Dann	Benign	0.40

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: rs121912276; hg19: chr20-61981404; COSMIC: COSV64718644; COSMIC: COSV64718644;