rs397514751

Positions:

• chr11-47332095-C-A
• chr11-47332095-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1 PM2 PP5

The NM_000256.3(MYBPC3):​c.3791G>T​(p.Cys1264Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MYBPC3 NM_000256.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:2
• Conservation: PhyloP100: 3.47

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 Uncertain_significance. Variant got 5 ACMG points.

• PM1: In a domain Ig-like C2-type 7 (size 93) in uniprot entity MYPC3_HUMAN there are 32 pathogenic changes around while only 0 benign (100%) in NM_000256.3
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-47332095-C-A is Pathogenic according to our data. Variant chr11-47332095-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 64613.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Likely_pathogenic=1}. Variant chr11-47332095-C-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.3791G>T	p.Cys1264Phe	missense_variant	33/35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.3791G>T	p.Cys1264Phe	missense_variant	33/35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.3791G>T	p.Cys1264Phe	missense_variant	32/34	5		ENSP00000382193.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Cardiomyopathy, dilated, 1MM Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Apr 01, 2010

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 30, 2014

p.Cys1264Phe (TGT>TTT): c.3791 G>T in exon 33 of the MYBPC3 gene (NM_000256.3). A published missense variant that is likely pathogenic was identified in the MYBPC3 gene. The C1264F variant in the MYBPC3 gene has been reported previously in association with familial dilated cardiomyopathy (DCM) (Hershberger R et al, 2010). Hershberger et al. (2010) identified C1264F in two related individuals with cardiomyopathy, which was absent in 246 control samples, and classified this variant as likely disease-causing. Additionally, the C1264F variant was not observed in approximately 6,200 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Furthermore, C1264F results in a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species. Mutations in surrounding residues (E1265V, C1266R, E1266Y) have been reported in association with cardiomyopathy, further supporting the functional importance of this region of the protein. Nevertheless, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function. Therefore, this variant is a strong candidate for a pathogenic mutation, however the possibility that it is a benign variant cannot be excluded. Mutations in the MYBPC3 gene have been reported in 20%-30% of patients with autosomal dominant familial hypertrophic cardiomyopathy, and have been reported less frequently in patients with autosomal dominant familial dilated cardiomyopathy (CirinoA et al., 2011; Hershberger R et al., 2009). The variant is found in HCM panel(s). -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 25, 2023

This sequence change replaces cysteine, which is neutral and slightly polar, with phenylalanine, which is neutral and non-polar, at codon 1264 of the MYBPC3 protein (p.Cys1264Phe). This variant is not present in population databases (gnomAD no frequency). 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: 64613). This missense change has been observed in individual(s) with dilated cardiomyopathy and/or hypertrophic cardiomyopathy (PMID: 20215591, 29121657, 33782553). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 06, 2024

The p.C1264F variant (also known as c.3791G>T), located in coding exon 33 of the MYBPC3 gene, results from a G to T substitution at nucleotide position 3791. The cysteine at codon 1264 is replaced by phenylalanine, an amino acid with highly dissimilar properties. This variant has been identified in individuals with dilated cardiomyopathy (DCM) (Hershberger RE et al. Circ Cardiovasc Genet, 2010 Apr;3:155-61) and hypertrophic cardiomyopathy (HCM) (Viswanathan SK et al. PLoS ONE, 2017 Nov;12:e0187948). This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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	0.73
CardioboostCm	Benign	0.017
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Benign	0.29	T;T;T
Eigen	Uncertain	0.30
Eigen_PC	Uncertain	0.31
FATHMM_MKL	Benign	0.21	N
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Uncertain	0.29	D
MetaRNN	Uncertain	0.72	D;D;D
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Benign	2.0	M;.;.
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-2.3	N;.;N
REVEL	Benign	0.28
Sift	Uncertain	0.014	D;.;D
Sift4G	Uncertain	0.0040	D;D;D
Vest4		0.70
MVP		0.81
MPC		0.76
ClinPred		0.96	D
GERP RS		5.5
Varity_R		0.60
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.12		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: rs397514751; hg19: chr11-47353646;