NM_000256.3:c.2833C>T

Variant names:

• chr11-47335114-G-A
• rs727503183
• NM_000256.3:c.2833C>T

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_000256.3(MYBPC3):​c.2833C>T​(p.Arg945Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000151 in 1,459,394 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R945Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.000015 (0 hom.)
• Consequence: MYBPC3 NM_000256.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 2.15
• Publications: 0 publications found

Genes affected

MYBPC3 (HGNC:7551): (myosin binding protein C3) MYBPC3 encodes the cardiac isoform of myosin-binding protein C. Myosin-binding protein C is a myosin-associated protein found in the cross-bridge-bearing zone (C region) of A bands in striated muscle. MYBPC3 is expressed exclusively in heart muscle and is a key regulator of cardiac contraction. Mutations in this gene are a frequent cause of familial hypertrophic cardiomyopathy. [provided by RefSeq, May 2022]

MYBPC3 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 4

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• left ventricular noncompaction 10

  Inheritance: AR, AD Classification: DEFINITIVE, MODERATE, LIMITED Submitted by: Ambry Genetics
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• atrial fibrillation

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• PP3: MetaRNN computational evidence supports a deleterious effect, 0.78

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.2833C>T	p.Arg945Trp	missense_variant	Exon 27 of 35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.2833C>T	p.Arg945Trp	missense_variant	Exon 27 of 35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.2833C>T	p.Arg945Trp	missense_variant	Exon 26 of 34	5		ENSP00000382193.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.0000122 AC: 3 AN: 246360 AF XY: 0.0000224

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000896

Gnomad OTH exome AF: 0.000168

GnomAD4 exome AF: 0.0000151 AC: 22 AN: 1459394 Hom.: 0 Cov.: 31 AF XY: 0.0000165 AC XY: 12 AN XY: 725944

African (AFR) AF: 0.0000300 AC: 1 AN: 33358

American (AMR) AF: 0.0000224 AC: 1 AN: 44552

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26074

East Asian (EAS) AF: 0.0000507 AC: 2 AN: 39478

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 85894

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53228

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5760

European-Non Finnish (NFE) AF: 0.0000153 AC: 17 AN: 1110776

Other (OTH) AF: 0.00 AC: 0 AN: 60274

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000450 Hom.: 0

Bravo AF: 0.0000189

ExAC AF: 0.00000827 AC: 1

EpiCase AF: 0.0000549

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:2

Dec 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 945 of the MYBPC3 protein (p.Arg945Trp). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This variant has not been reported in the literature in individuals affected with MYBPC3-related conditions. ClinVar contains an entry for this variant (Variation ID: 164060). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Sep 23, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with tryptophan at codon 945 of the MYBPC3 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 3/246360 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not specified Uncertain:1

Jul 21, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Arg945Trp variant in MYBPC3 has not been previously reported in individuals with cardiomyopathy or in large population studies. Arginine (Arg) at position 9 45 is not conserved in mammals or evolutionarily distant species and the change to Tryptophan (Trp) was predicted to be benign using a computational tool clinic ally validated by our laboratory. This tool's benign prediction is estimated to be correct 89% of the time (Jordan 2011). In summary, the clinical significance of the Arg945Trp variant is uncertain. -

Cardiomyopathy Uncertain:1

Sep 30, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with tryptophan at codon 945 of the MYBPC3 protein. Computational prediction tool is inconclusive regarding the impact of this variant on protein structure and function. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MYBPC3-related disorders in the literature. This variant has been identified in 3/246360 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

not provided Uncertain:1

Dec 21, 2021

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hypertrophic cardiomyopathy 4 Uncertain:1

May 06, 2021

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as VUS-3B. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with hypertrophic cardiomyopathy 4 (MIM#115197). (I) 0108 - This gene is associated with both recessive and dominant disease. Heterozygous variants are frequently reported in adult onset conditions, however recessive inheritance results in a more severe early onset phenotype (OMIM). (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to tryptophan. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (3 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v3) (4 heterozygotes, 0 homozygotes). (I) 0502 - Missense variant with conflicting in silico predictions and uninformative conservation. (I) 0600 - Variant is located in the annotated Fibronectin type III 2 domain (NCBI, Uniprot). (I) 0710 - Other missense variants comparable to the one identified in this case have inconclusive previous evidence for pathogenicity. Two different variants in the same codon resulting in a change to a leucine and a glutamine have been reported as VUS (ClinVar, PMID: 29875424). (I) 0808 - Previous reports of pathogenicity for this variant are conflicting. This variant has been reported as a VUS and also found in a healthy individual (ClinVar, PMID: 24510615). (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Cardiovascular phenotype Uncertain:1

Feb 05, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R945W variant (also known as c.2833C>T), located in coding exon 27 of the MYBPC3 gene, results from a C to T substitution at nucleotide position 2833. The arginine at codon 945 is replaced by tryptophan, an amino acid with dissimilar properties. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.41
CardioboostCm	Benign	0.085
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.46	T;T;T
Eigen	Uncertain	0.60
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.78	D;D;D
MetaSVM	Uncertain	-0.15	T
MutationAssessor	Pathogenic	3.8	H;.;.
PhyloP100		2.2
PrimateAI	Benign	0.41	T
PROVEAN	Uncertain	-4.2	D;.;D
REVEL	Uncertain	0.43
Sift	Benign	0.11	T;.;T
Sift4G	Uncertain	0.025	D;D;D
Vest4		0.64
MVP		0.87
MPC		0.84
ClinPred		0.98	D
GERP RS		4.4
Varity_R		0.61
gMVP		0.82
Mutation Taster		=75/25	polymorphism

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: rs727503183; hg19: chr11-47356665;