2-232531600-C-T

Variant names:

• chr2-232531600-C-T
• rs1292476417
• NM_000751.3:c.991C>T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_000751.3(CHRND):​c.991C>T​(p.Leu331Phe) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,740 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 Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: CHRND NM_000751.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.99

Genes affected

CHRND (HGNC:1965): (cholinergic receptor nicotinic delta subunit) The acetylcholine receptor of muscle has 5 subunits of 4 different types: 2 alpha and 1 each of beta, gamma and delta subunits. After acetylcholine binding, the receptor undergoes an extensive conformation change that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Defects in this gene are a cause of multiple pterygium syndrome lethal type (MUPSL), congenital myasthenic syndrome slow-channel type (SCCMS), and congenital myasthenic syndrome fast-channel type (FCCMS). Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2015]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.91

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHRND	NM_000751.3	c.991C>T	p.Leu331Phe	missense_variant	Exon 9 of 12	ENST00000258385.8	NP_000742.1
CHRND	NM_001256657.2	c.946C>T	p.Leu316Phe	missense_variant	Exon 8 of 11		NP_001243586.1
CHRND	NM_001311196.2	c.688C>T	p.Leu230Phe	missense_variant	Exon 9 of 12		NP_001298125.1
CHRND	NM_001311195.2	c.409C>T	p.Leu137Phe	missense_variant	Exon 7 of 10		NP_001298124.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHRND	ENST00000258385.8	c.991C>T	p.Leu331Phe	missense_variant	Exon 9 of 12	1	NM_000751.3	ENSP00000258385.3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251406 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135884

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: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461740 Hom.: 0 Cov.: 33 AF XY: 0.00000138 AC XY: 1 AN XY: 727176

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Lethal multiple pterygium syndrome Uncertain:1

Apr 20, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces leucine with phenylalanine at codon 331 of the CHRND protein (p.Leu331Phe). The leucine residue is highly conserved and there is a small physicochemical difference between leucine and phenylalanine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a CHRND-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.48
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.88	.;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.97	D;D
M_CAP	Uncertain	0.16	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Pathogenic	4.5	.;H
PrimateAI	Pathogenic	0.80	T
PROVEAN	Uncertain	-4.0	D;D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	.;D
Vest4		0.84
MutPred		0.71		.;Loss of sheet (P = 0.302);
MVP		1.0
MPC		0.92
ClinPred		1.0	D
GERP RS		6.1
Varity_R		0.93
gMVP		0.75

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: rs1292476417; hg19: chr2-233396310;