2-174757590-C-A

Position:

• chr2-174757590-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000079.4(CHRNA1):​c.320G>T​(p.Arg107Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,674 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CHRNA1 NM_000079.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.574

Genes affected

CHRNA1 (HGNC:1955): (cholinergic receptor nicotinic alpha 1 subunit) The muscle acetylcholine receptor consiststs of 5 subunits of 4 different types: 2 alpha subunits and 1 each of the beta, gamma, and delta subunits. This gene encodes an alpha subunit that plays a role in acetlycholine binding/channel gating. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Nov 2012]

ENSG00000236449 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a topological_domain Extracellular (size 211) in uniprot entity ACHA_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000079.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.36373794).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNA1	NM_000079.4	c.320G>T	p.Arg107Leu	missense_variant	4/9	ENST00000348749.9	NP_000070.1
CHRNA1	NM_001039523.3	c.395G>T	p.Arg132Leu	missense_variant	5/10		NP_001034612.1
CHRNA1	XM_017003256.2	c.416G>T	p.Arg139Leu	missense_variant	4/9		XP_016858745.1
CHRNA1	XM_017003257.2	c.341G>T	p.Arg114Leu	missense_variant	3/8		XP_016858746.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNA1	ENST00000348749.9	c.320G>T	p.Arg107Leu	missense_variant	4/9	1	NM_000079.4	ENSP00000261008.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251376 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135856

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

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: 6.84e-7 AC: 1 AN: 1461674 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727158

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lethal multiple pterygium syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 06, 2023

This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 107 of the CHRNA1 protein (p.Arg107Leu). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with CHRNA1-related conditions. ClinVar contains an entry for this variant (Variation ID: 281666). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt CHRNA1 protein function with a negative predictive value of 80%. 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Jul 10, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Uncertain	0.027	T
BayesDel_noAF	Benign	-0.12
CADD	Benign	15
DANN	Benign	0.94
DEOGEN2	Benign	0.24	.;T;T;T;.
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.24
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.89	D;D;D;D;D
M_CAP	Benign	0.049	D
MetaRNN	Benign	0.36	T;T;T;T;T
MetaSVM	Benign	-0.89	T
MutationAssessor	Benign	0.46	.;N;.;.;.
PrimateAI	Benign	0.28	T
PROVEAN	Benign	0.040	N;N;N;.;N
REVEL	Uncertain	0.36
Sift	Benign	1.0	T;T;T;.;T
Sift4G	Benign	1.0	T;T;T;.;T
Polyphen		0.0, 0.0010	.;B;.;.;B
Vest4		0.61
MutPred		0.61		.;Loss of methylation at K129 (P = 0.1011);.;.;.;
MVP		0.57
MPC		0.31
ClinPred		0.31	T
GERP RS		4.3
Varity_R		0.42
gMVP		0.71

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: rs376844505; hg19: chr2-175622318;