2-232539749-T-C

Position:

• chr2-232539749-T-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_005199.5(CHRNG):​c.2T>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000479 in 1,461,578 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: CHRNG NM_005199.5 start_lost
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.420

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
CHRNG	NM_005199.5	c.2T>C	p.Met1?	start_lost	1/12	ENST00000651502.1	NP_005190.4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHRNG	ENST00000651502.1	c.2T>C	p.Met1?	start_lost	1/12		NM_005199.5	ENSP00000498757.1
CHRNG	ENST00000389492.3	c.2T>C	p.Met1?	start_lost	1/11	1		ENSP00000374143.3
CHRNG	ENST00000485094.1	n.23T>C		non_coding_transcript_exon_variant	1/5	1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461578 Hom.: 0 Cov.: 33 AF XY: 0.00000413 AC XY: 3 AN XY: 727092

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000756

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive multiple pterygium syndrome;C1854678:Lethal multiple pterygium syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Mar 19, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	-0.010
CADD	Benign	20
DANN	Uncertain	0.99
DEOGEN2	Benign	0.040	T;.
Eigen	Benign	-0.35
Eigen_PC	Benign	-0.29
FATHMM_MKL	Benign	0.59	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Benign	-0.51	T
PROVEAN	Benign	-0.78	N;N
REVEL	Uncertain	0.46
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.010	B;.
Vest4		0.77
MutPred		0.97		Loss of stability (P = 0.0046);Loss of stability (P = 0.0046);
MVP		0.89
ClinPred		0.99	D
GERP RS		3.8
Varity_R		0.89

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

Publications

LitVar

Other links and lift over

dbSNP: rs1691973759; hg19: chr2-233404459;