2-232539749-T-C

Variant names:

• chr2-232539749-T-C
• rs1691973759
• NM_005199.5:c.2T>C

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

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. Variant has been reported in ClinVar as Likely pathogenic (★).

• 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
• Publications: 0 publications found

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: Ambry Genetics, G2P, 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: PanelApp Australia, Labcorp Genetics (formerly Invitae), Orphanet
• transient neonatal myasthenia gravis

  Inheritance: AR Classification: STRONG Submitted by: Genomics England PanelApp

ACMG classification

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

• PVS1: Start lost variant, next in-frame start position is after 3 pathogenic variants. Next in-frame start position is after 34 codons. Genomic position: 232540036. Lost 0.064 part of the original CDS.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-232539749-T-C is Pathogenic according to our data. Variant chr2-232539749-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3586169.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRNG	NM_005199.5	c.2T>C	p.Met1?	start_lost	Exon 1 of 12	ENST00000651502.1	NP_005190.4

Ensembl

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

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

American (AMR) AF: 0.00 AC: 0 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.0000756 AC: 3 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86250

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53238

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5714

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111966

Other (OTH) AF: 0.00 AC: 0 AN: 60382

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

Mar 19, 2024

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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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
PhyloP100		0.42
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
PromoterAI		0.0091	Neutral
Varity_R		0.89
Mutation Taster		=24/176	disease causing

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: rs1691973759; hg19: chr2-233404459;