chr17-4899468-G-T

Position:

• chr17-4899468-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000080.4(CHRNE):​c.1032C>A​(p.His344Gln) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000696 in 1,435,752 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/23 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★). Another nucleotide change resulting in same amino acid change has been previously reported as Uncertain significancein ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. H344D) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 7.0e-7 (0 hom.)
• Consequence: CHRNE NM_000080.4 missense, splice_region
• Scores: Splicing: ADA: 0.00003026
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.767

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

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.21193743).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNE	NM_000080.4	c.1032C>A	p.His344Gln	missense_variant, splice_region_variant	9/12	ENST00000649488.2
CHRNE	XM_017024115.2	c.996C>A	p.His332Gln	missense_variant, splice_region_variant	10/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNE	ENST00000649488.2	c.1032C>A	p.His344Gln	missense_variant, splice_region_variant	9/12		NM_000080.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.96e-7 AC: 1 AN: 1435752 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 711656

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: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000168

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Congenital myasthenic syndrome 4A Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 23, 2021

This sequence change replaces histidine, which is basic and polar, with glutamine, which is neutral and polar, at codon 344 of the CHRNE protein (p.His344Gln). 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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glutamine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.097
BayesDel_addAF	Benign	-0.10	T
BayesDel_noAF	Benign	-0.38
CADD	Benign	3.5
DANN	Benign	0.75
DEOGEN2	Benign	0.13	T;T;.
Eigen	Benign	-1.1
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.24	N
LIST_S2	Benign	0.40	.;T;T
M_CAP	Pathogenic	0.42	D
MetaRNN	Benign	0.21	T;T;T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	-0.38	N;N;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Benign	0.57	N;.;.
REVEL	Benign	0.19
Sift	Benign	0.93	T;.;.
Sift4G	Benign	0.52	T;.;.
Polyphen		0.050	B;B;.
Vest4		0.16
MutPred		0.46		Loss of methylation at R341 (P = 0.0481);Loss of methylation at R341 (P = 0.0481);.;
MVP		0.80
MPC		0.18
ClinPred		0.11	T
GERP RS		-1.2
Varity_R		0.11
gMVP		0.45

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000030
dbscSNV1_RF	Benign	0.012
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: rs144047383; hg19: chr17-4802763;