chr11-47348475-C-T

Position:

• chr11-47348475-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000256.3(MYBPC3):​c.721G>A​(p.Val241Met) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,236 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. V241L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYBPC3 NM_000256.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 6.13

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a strand (size 7) in uniprot entity MYPC3_HUMAN there are 7 pathogenic changes around while only 3 benign (70%) in NM_000256.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.87

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYBPC3	NM_000256.3	c.721G>A	p.Val241Met	missense_variant	6/35	ENST00000545968.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYBPC3	ENST00000545968.6	c.721G>A	p.Val241Met	missense_variant	6/35	5	NM_000256.3	P4
MYBPC3	ENST00000399249.6	c.721G>A	p.Val241Met	missense_variant	6/34	5		A2
MYBPC3	ENST00000544791.1	c.721G>A	p.Val241Met	missense_variant, NMD_transcript_variant	6/27	5

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461236 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726878

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Aug 23, 2023	This missense variant replaces valine with methionine at codon 241 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 MYBPC3-related disorders in the literature. This variant has not been identified 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 09, 2023	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. 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. ClinVar contains an entry for this variant (Variation ID: 418351). This variant has not been reported in the literature in individuals affected with MYBPC3-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 241 of the MYBPC3 protein (p.Val241Met). -

Hypertrophic cardiomyopathy 4;C3715165:Left ventricular noncompaction 10 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Nov 21, 2021

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 29, 2018

The V241M variant has not been published as a pathogenic variant or been reported as a benign polymorphism to our knowledge. The V241M variant was not observed in approximately 6,300 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Although the V241M variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties; it is located in the Ig-like C2-type 1 functional domain of the MYBPC3 gene. This substitution occurs at a position that is well conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. Missense variants in nearby residues (Y237H, Y237C, Y237S, R238H, E240D, S242P) have been reported in Human Gene Mutation Database in association with cardiomyopathy (Stenson P et al., 2014), supporting the functional importance of this region of the protein. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 15, 2017

The p.V241M variant (also known as c.721G>A), located in coding exon 6 of the MYBPC3 gene, results from a G to A substitution at nucleotide position 721. The valine at codon 241 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.67
CardioboostCm	Pathogenic	0.92
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	26
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.75	D;T;T
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Uncertain	0.26	D
MetaRNN	Pathogenic	0.87	D;D;D
MetaSVM	Uncertain	0.35	D
MutationAssessor	Uncertain	2.6	M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-2.5	D;D;D
REVEL	Pathogenic	0.69
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0010	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.77
MutPred		0.73		Gain of ubiquitination at K244 (P = 0.0701);Gain of ubiquitination at K244 (P = 0.0701);Gain of ubiquitination at K244 (P = 0.0701);
MVP		0.87
MPC		0.83
ClinPred		0.98	D
GERP RS		5.1
Varity_R		0.64
gMVP		0.72

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: rs886039000; hg19: chr11-47370026; COSMIC: COSV57031455;