rs730880608

chr11-47332090-A-G

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PM5 PP3_Strong

The NM_000256.3(MYBPC3):c.3796T>C(p.Cys1266Arg) 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C1266W) has been classified 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: 8.94

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 Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_000256.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr11-47332089-C-T is described in Lovd as [Likely_pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.955

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYBPC3	NM_000256.3	c.3796T>C	p.Cys1266Arg	missense_variant	33/35	ENST00000545968.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYBPC3	ENST00000545968.6	c.3796T>C	p.Cys1266Arg	missense_variant	33/35	5	NM_000256.3	P4
MYBPC3	ENST00000399249.6	c.3796T>C	p.Cys1266Arg	missense_variant	32/34	5		A2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Nov 24, 2015

p.Cys1266Arg (C1266R) TGC>CGC: c.3796 T>C in exon 33 of the MYBPC3 gene (NM_000256.3)The C1266R mutation in the MYBPC3 gene has been reported with another MYBPC3 mutation (E1265V) in one 46-year-old male with a diagnosis of HCM (Maron B et al., 2012). Maron et al. (2012) reported this mutation was not observed in 300 unrelated healthy, ethnically-matched chromosomes. Furthermore, the C1266R mutation was not observed in approximately 6,000 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. C1266R 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. A mutation in the same residue (C1266Y) and mutations in nearby residues (G1260D, C1264F, E1265V, L1268Q) have been reported in association with cardiomyopathy, further supporting the functional importance of this residue and region of the protein. The variant is found in HCM panel(s). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 06, 2018

The p.C1266R variant (also known as c.3796T>C), located in coding exon 33 of the MYBPC3 gene, results from a T to C substitution at nucleotide position 3796. The cysteine at codon 1266 is replaced by arginine, an amino acid with highly dissimilar properties. This variant has been detected in conjunction with a different alteration in MYBPC3 in a patient with hypertrophic cardiomyopathy (HCM) (Maron BJ et al. Heart Rhythm. 2012 Jan;9:57-63). Other alterations involving the same amino acid, including p.C1266Y (c.3797G>A) and p.C1266W (c.3798C>G), also have been reported in HCM cohorts; however, clinical details were limited (Page SP et al. Circ Cardiovasc Genet. 2012 Apr;5:156-66; Lopes LR et al. Heart, 2015 Feb;101:294-301; Walsh R et al. Genet. Med., 2017 02;19:192-203). 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	0.96
CardioboostCm	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
Cadd	Pathogenic	32
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.75	D;T;T
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.91	D;D;D
M_CAP	Pathogenic	0.58	D
MetaRNN	Pathogenic	0.95	D;D;D
MetaSVM	Uncertain	-0.015	T
MutationAssessor	Uncertain	2.6	M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.71	T
PROVEAN	Pathogenic	-11	D;.;D
REVEL	Pathogenic	0.74
Sift	Uncertain	0.0010	D;.;D
Sift4G	Pathogenic	0.0	D;D;D
Vest4		0.98
MVP		0.87
MPC		1.1
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.99
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.16		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: rs730880608; hg19: chr11-47353641;