Genetic Variant CHRNG:c.55+1G>T (chr2-232539803-G-T) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_005199.5(CHRNG):c.55+1G>T variant causes a splice donor, intron change. The variant allele was found at a frequency of 0.000000684 in 1,461,506 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

Frequency

Genomes: not found (cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

CHRNG
NM_005199.5 splice_donor, intron

Scores

Splicing: ADA: 0.9999

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 4.83

Publications

0 publications found

Variant links:

Genes affected

CHRNG (HGNC:1967): (cholinergic receptor nicotinic gamma subunit) The mammalian muscle-type acetylcholine receptor is a transmembrane pentameric glycoprotein with two alpha subunits, one beta, one delta, and one epsilon (in adult skeletal muscle) or gamma (in fetal and denervated muscle) subunit. This gene, which encodes the gamma subunit, is expressed prior to the thirty-third week of gestation in humans. The gamma subunit of the acetylcholine receptor plays a role in neuromuscular organogenesis and ligand binding and disruption of gamma subunit expression prevents the correct localization of the receptor in cell membranes. Mutations in this gene cause Escobar syndrome and a lethal form of multiple pterygium syndrome. Muscle-type acetylcholine receptor is the major antigen in the autoimmune disease myasthenia gravis.[provided by RefSeq, Sep 2009]

CHRNG Gene-Disease associations (from GenCC):

autosomal recessive multiple pterygium syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Orphanet
CHRNG-associated hypo-akinesia disorder of prenatal onset
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
lethal multiple pterygium syndrome
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet
transient neonatal myasthenia gravis
Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp

CHRNG links:

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ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.071428575 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PM2

Very rare variant in population databases, with high coverage;

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005199.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNG	NM_005199.5	MANE Select	c.55+1G>T		splice_donor intron	N/A	NP_005190.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein	UniProt
CHRNG	ENST00000651502.1	MANE Select	c.55+1G>T	splice_donor intron	N/A	ENSP00000498757.1	P07510-1
CHRNG	ENST00000389492.3	TSL:1	c.55+1G>T	splice_donor intron	N/A	ENSP00000374143.3	P07510-2
CHRNG	ENST00000485094.1	TSL:1	n.76+1G>T	splice_donor intron	N/A

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461506

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727052

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33468

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86240

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53350

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5560

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111976

Other (OTH)

AF:

0.00

AC:

AN:

60368

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Benign

-0.31

CADD

Pathogenic

(source)

DANN

Benign

0.97

Eigen

Pathogenic

0.73

Eigen_PC

Uncertain

0.47

FATHMM_MKL

Benign

0.56

PhyloP100

4.8

GERP RS

3.8

PromoterAI

0.025

Neutral

(source)

Mutation Taster

=9/91

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.78

SpliceAI score (max)

0.20

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.20

Position offset: -1

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over