2-232540061-G-C

Variant names:

• chr2-232540061-G-C
• rs148468628
• NM_005199.5:c.125G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PP3_Strong

The NM_005199.5(CHRNG):​c.125G>C​(p.Arg42Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000109 in 1,461,876 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. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R42Q) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000011 (0 hom.)
• Consequence: CHRNG NM_005199.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.76
• Publications: 7 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: 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

ACMG classification

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

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.978

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.125G>C	p.Arg42Pro	missense	Exon 2 of 12	NP_005190.4

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CHRNG	ENST00000651502.1	MANE Select	c.125G>C	p.Arg42Pro	missense	Exon 2 of 12	ENSP00000498757.1	P07510-1
	CHRNG	ENST00000389492.3	TSL:1	c.125G>C	p.Arg42Pro	missense	Exon 2 of 11	ENSP00000374143.3	P07510-2
	CHRNG	ENST00000485094.1	TSL:1	n.146G>C		non_coding_transcript_exon	Exon 2 of 5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000637 AC: 16 AN: 251312 AF XY: 0.0000368

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000405

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000109 AC: 16 AN: 1461876 Hom.: 0 Cov.: 33 AF XY: 0.00000825 AC XY: 6 AN XY: 727240

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

American (AMR) AF: 0.000291 AC: 13 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112000

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome Cov.: 33

Alfa AF: 0.00000323 Hom.: 3

Bravo AF: 0.0000113

ExAC AF: 0.0000330 AC: 4

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Pathogenic	0.33
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	D
Eigen	Uncertain	0.55
Eigen_PC	Uncertain	0.35
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.76	T
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Pathogenic	3.4	M
PhyloP100		7.8
PrimateAI	Uncertain	0.48	T
PROVEAN	Pathogenic	-5.9	D
REVEL	Pathogenic	0.87
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0030	D
Polyphen		1.0	D
Vest4		0.85
MutPred		0.86		Gain of catalytic residue at R42 (P = 0.0165)
MVP		0.88
MPC		0.71
ClinPred		0.93	D
GERP RS		4.0
PromoterAI		0.020	Neutral
Varity_R		0.92
Mutation Taster		=37/63	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: rs148468628; hg19: chr2-233404771;