rs1064795871

Variant names:

• chr17-4901999-G-A
• rs1064795871
• NM_000080.4:c.433C>T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000080.4(CHRNE):​c.433C>T​(p.Arg145Cys) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,802 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 (★★). Synonymous variant affecting the same amino acid position (i.e. R145R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: CHRNE NM_000080.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.01
• Publications: 0 publications found

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]

C17orf107 (HGNC:37238): (chromosome 17 open reading frame 107)

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 8 uncertain in NM_000080.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.929

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNE	NM_000080.4	c.433C>T	p.Arg145Cys	missense_variant	Exon 5 of 12	ENST00000649488.2	NP_000071.1
C17orf107	NM_001145536.2	c.*1466G>A		3_prime_UTR_variant	Exon 3 of 3	ENST00000381365.4	NP_001139008.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRNE	ENST00000649488.2	c.433C>T	p.Arg145Cys	missense_variant	Exon 5 of 12		NM_000080.4	ENSP00000497829.1
C17orf107	ENST00000381365.4	c.*1466G>A		3_prime_UTR_variant	Exon 3 of 3	2	NM_001145536.2	ENSP00000370770.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461802 Hom.: 0 Cov.: 37 AF XY: 0.00 AC XY: 0 AN XY: 727198

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53330

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital myasthenic syndrome 4A Uncertain:1

Nov 13, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 145 of the CHRNE protein (p.Arg145Cys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CHRNE-related conditions. ClinVar contains an entry for this variant (Variation ID: 422577). 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 expected to disrupt CHRNE protein function with a positive predictive value of 95%. 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

Nov 02, 2016

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The R145C variant in the CHRNE gene has not been reported previously as a pathogenic variant, nor as a benign variant, to our knowledge. This variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The R145C variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species, and in silico analysis predicts this variant is probably damaging to the protein structure/function. We interpret R145C as a variant of uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.84	D;D
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.97	.;D
M_CAP	Pathogenic	0.42	D
MetaRNN	Pathogenic	0.93	D;D
MetaSVM	Uncertain	0.47	D
MutationAssessor	Uncertain	2.3	M;M
PhyloP100		5.0
PrimateAI	Uncertain	0.52	T
PROVEAN	Pathogenic	-6.4	D;.
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0050	D;.
Sift4G	Pathogenic	0.0	D;.
Polyphen		1.0	D;D
Vest4		0.75
MutPred		0.73		Gain of catalytic residue at V147 (P = 0.0796);Gain of catalytic residue at V147 (P = 0.0796);
MVP		0.92
MPC		0.80
ClinPred		0.99	D
GERP RS		4.8
Varity_R		0.74
gMVP		0.88

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

Other links and lift over

dbSNP: rs1064795871; hg19: chr17-4805294; COSMIC: COSV99036232; COSMIC: COSV99036232;