rs397515928

Positions:

• chr11-47341227-A-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_000256.3(MYBPC3):​c.1808T>C​(p.Ile603Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MYBPC3 NM_000256.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 8.84

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 8 ACMG points.

• PM1: In a domain Ig-like C2-type 4 (size 89) in uniprot entity MYPC3_HUMAN there are 31 pathogenic changes around while only 3 benign (91%) in NM_000256.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.957

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.1808T>C	p.Ile603Thr	missense_variant	19/35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.1808T>C	p.Ile603Thr	missense_variant	19/35	5	NM_000256.3	ENSP00000442795	P4
MYBPC3	ENST00000399249.6	c.1808T>C	p.Ile603Thr	missense_variant	18/34	5		ENSP00000382193	A2
MYBPC3	ENST00000544791.1	c.1808T>C	p.Ile603Thr	missense_variant, NMD_transcript_variant	19/27	5		ENSP00000444259

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jun 26, 2012

The Ile603Thr variant in MYBPC3 has not been reported in the literature nor prev iously identified in >3600 individuals (>2200 Caucasian) tested by our laborator y. Computational analyses (biochemical amino acid properties, conservation, Alig nGVGD, PolyPhen2, and SIFT) suggest that this variant may impact the protein, th ough this information is not predictive enough to determine pathogenicity. Addit ional studies are needed to fully assess the clinical significance of this varia nt. -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 09, 2022

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. This variant disrupts the p.Ile603 amino acid residue in MYBPC3. Other variant(s) that disrupt this residue have been observed in individuals with MYBPC3-related conditions (PMID: 33782553), which suggests that this may be a clinically significant amino acid residue. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 42570). This missense change has been observed in individuals with hypertrophic cardiomyopathy (PMID: 33782553; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 603 of the MYBPC3 protein (p.Ile603Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
CardioboostCm	Uncertain	0.54
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D;T;T
Eigen	Pathogenic	0.88
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D;D
M_CAP	Pathogenic	0.52	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Uncertain	0.73	D
MutationAssessor	Pathogenic	3.7	H;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.66	T
PROVEAN	Uncertain	-4.4	D;.;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D;.;D
Sift4G	Pathogenic	0.0010	D;D;D
Vest4		0.98
MVP		0.95
MPC		0.90
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.90
gMVP		0.94

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: rs397515928; hg19: chr11-47362778;