chr17-4898873-G-T

Position:

• chr17-4898873-G-T

Variant summary

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

The NM_000080.4(CHRNE):​c.1345C>A​(p.Arg449Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000699 in 1,430,516 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 Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: CHRNE NM_000080.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 2.33

Genes affected

CHRNE (HGNC:1966): (cholinergic receptor nicotinic epsilon subunit) Acetylcholine receptors at mature mammalian neuromuscular junctions are pentameric protein complexes composed of four subunits in the ratio of two alpha subunits to one beta, one epsilon, and one delta subunit. The acetylcholine receptor changes subunit composition shortly after birth when the epsilon subunit replaces the gamma subunit seen in embryonic receptors. Mutations in the epsilon subunit are associated with congenital myasthenic syndrome. [provided by RefSeq, Sep 2009]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM1: In a topological_domain Cytoplasmic (size 127) in uniprot entity ACHE_HUMAN there are 8 pathogenic changes around while only 0 benign (100%) in NM_000080.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.3242401).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNE	NM_000080.4	c.1345C>A	p.Arg449Ser	missense_variant	12/12	ENST00000649488.2	NP_000071.1
CHRNE	XM_017024115.2	c.1309C>A	p.Arg437Ser	missense_variant	13/13		XP_016879604.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNE	ENST00000649488.2	c.1345C>A	p.Arg449Ser	missense_variant	12/12		NM_000080.4	ENSP00000497829	P1
CHRNE	ENST00000649830.1	c.521C>A	p.Ala174Glu	missense_variant	11/11			ENSP00000496907
CHRNE	ENST00000572438.1	n.1031C>A		non_coding_transcript_exon_variant	7/7	5
CHRNE	ENST00000652550.1	n.1071C>A		non_coding_transcript_exon_variant	4/4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000103 AC: 2 AN: 195048 Hom.: 0 AF XY: 0.0000191 AC XY: 2 AN XY: 104736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000680

Gnomad SAS exome AF: 0.0000391

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.99e-7 AC: 1 AN: 1430516 Hom.: 0 Cov.: 34 AF XY: 0.00000141 AC XY: 1 AN XY: 708734

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000122

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000832 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital myasthenic syndrome 4A Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 14, 2022

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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 CHRNE protein function. ClinVar contains an entry for this variant (Variation ID: 959504). This variant has not been reported in the literature in individuals affected with CHRNE-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 449 of the CHRNE protein (p.Arg449Ser). -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

May 19, 2023

In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Congenital myasthenic syndrome Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

May 17, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Uncertain	0.066	T
BayesDel_noAF	Benign	-0.14
CADD	Uncertain	24
DANN	Uncertain	0.99
Eigen	Benign	-0.031
Eigen_PC	Benign	0.079
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Benign	0.18	T
M_CAP	Uncertain	0.087	D
MetaRNN	Benign	0.32	T
MutationTaster	Benign	0.51	D
ClinPred		0.70	D
GERP RS		4.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.20		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.20		Position offset: 18

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs149083639; hg19: chr17-4802168;