chr17-4899467-C-T

Position:

• chr17-4899467-C-T

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1 PP3_Strong PP5_Very_Strong

The NM_000080.4(CHRNE):​c.1032+1G>A variant causes a splice donor change. The variant allele was found at a frequency of 0.00000418 in 1,434,770 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000042 (0 hom.)
• Consequence: CHRNE NM_000080.4 splice_donor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 5.45

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 Pathogenic. Variant got 20 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 17-4899467-C-T is Pathogenic according to our data. Variant chr17-4899467-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1501328.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
CHRNE	NM_000080.4	c.1032+1G>A		splice_donor_variant		ENST00000649488.2
CHRNE	XM_017024115.2	c.996+1G>A		splice_donor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
CHRNE	ENST00000649488.2	c.1032+1G>A		splice_donor_variant			NM_000080.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD3 exomes AF: 0.00000490 AC: 1 AN: 203960 Hom.: 0 AF XY: 0.00000906 AC XY: 1 AN XY: 110420

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.0000112

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000418 AC: 6 AN: 1434770 Hom.: 0 Cov.: 34 AF XY: 0.00000844 AC XY: 6 AN XY: 711106

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: 0.00000545

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Congenital myasthenic syndrome 4A Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 11, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 07, 2021	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Studies have shown that disruption of this splice site results in skipping of exon 9 and introduces a premature termination codon (PMID: 11408331). The resulting mRNA is expected to undergo nonsense-mediated decay. Disruption of this splice site has been observed in individual(s) with congenital myasthenic syndrome (PMID: 11408331). 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 affects a donor splice site in intron 9 of the CHRNE gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.15
CADD	Pathogenic	27
DANN	Uncertain	0.99
Eigen	Pathogenic	0.80
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.95	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.96		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1458613529; hg19: chr17-4802762;