15-78596663-A-T

Position:

• chr15-78596663-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000743.5(CHRNA3):​c.1459T>A​(p.Cys487Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,036 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: CHRNA3 NM_000743.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.30

Genes affected

CHRNA3 (HGNC:1957): (cholinergic receptor nicotinic alpha 3 subunit) This locus encodes a member of the nicotinic acetylcholine receptor family of proteins. Members of this family of proteins form pentameric complexes comprised of both alpha and beta subunits. This locus encodes an alpha-type subunit, as it contains characteristic adjacent cysteine residues. The encoded protein is a ligand-gated ion channel that likely plays a role in neurotransmission. Polymorphisms in this gene have been associated with an increased risk of smoking initiation and an increased susceptibility to lung cancer. Alternatively spliced transcript variants have been described. [provided by RefSeq, Nov 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.886

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNA3	NM_000743.5	c.1459T>A	p.Cys487Ser	missense_variant	6/6	ENST00000326828.6	NP_000734.2
CHRNA3	XM_006720382.4	c.1258T>A	p.Cys420Ser	missense_variant	6/6		XP_006720445.1
CHRNA3	NM_001166694.2	c.1390-3472T>A		intron_variant			NP_001160166.1
CHRNA3	NR_046313.2	n.1661T>A		non_coding_transcript_exon_variant	6/8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNA3	ENST00000326828.6	c.1459T>A	p.Cys487Ser	missense_variant	6/6	1	NM_000743.5	ENSP00000315602	P1
CHRNA3	ENST00000348639.7	c.1390-3472T>A		intron_variant		1		ENSP00000267951
CHRNA3	ENST00000559002.5	n.70T>A		non_coding_transcript_exon_variant	1/2	1
CHRNA3	ENST00000559658.5	c.1459T>A	p.Cys487Ser	missense_variant, NMD_transcript_variant	6/8	2		ENSP00000452896

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000400 AC: 1 AN: 250236 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135356

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000293

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461036 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726868

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000677

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 03, 2022

Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant has not been reported in the literature in individuals affected with CHRNA3-related conditions. This sequence change replaces cysteine, which is neutral and slightly polar, with serine, which is neutral and polar, at codon 487 of the CHRNA3 protein (p.Cys487Ser). This variant is present in population databases (rs772596477, gnomAD 0.003%). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.63
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.36
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.79	D
Eigen	Pathogenic	0.72
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.88	D
M_CAP	Uncertain	0.12	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Uncertain	0.45	D
MutationAssessor	Uncertain	2.1	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.84	D
PROVEAN	Pathogenic	-7.6	D
REVEL	Pathogenic	0.87
Sift	Benign	0.12	T
Sift4G	Benign	0.25	T
Polyphen		1.0	D
Vest4		0.84
MutPred		0.62		Gain of glycosylation at C487 (P = 0.1292);
MVP		0.92
MPC		1.0
ClinPred		0.99	D
GERP RS		5.1
Varity_R		0.62
gMVP		0.69

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: rs772596477; hg19: chr15-78889005;