rs1555120261

Positions:

• chr11-47332566-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP3_Moderate PP5

The NM_000256.3(MYBPC3):​c.3627G>A​(p.Lys1209=) variant causes a splice region, synonymous change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYBPC3 NM_000256.3 splice_region, synonymous
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 7.56

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.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 11-47332566-C-T is Pathogenic according to our data. Variant chr11-47332566-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 444251.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.3627G>A	p.Lys1209=	splice_region_variant, synonymous_variant	32/35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.3627G>A	p.Lys1209=	splice_region_variant, synonymous_variant	32/35	5	NM_000256.3	ENSP00000442795	P4
MYBPC3	ENST00000399249.6	c.3627G>A	p.Lys1209=	splice_region_variant, synonymous_variant	31/34	5		ENSP00000382193	A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Apr 01, 2017

- -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 26, 2020

This sequence change affects codon 1209 of the MYBPC3 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MYBPC3 protein. This variant also falls at the last nucleotide of exon 32 of the MYBPC3 coding sequence, which is part of the consensus splice site for this exon. 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. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with MYBPC3-related disease. ClinVar contains an entry for this variant (Variation ID: 444251). This variant is not present in population databases (ExAC no frequency). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 23, 2021

The c.3627G>A (p.K1209K) alteration is located in exon 32 (coding exon 32) of the MYBPC3 gene. This alteration consists of a G to A substitution at nucleotide position 3627. This nucleotide substitution does not change the amino acid at codon 1209. However, this change occurs in the last nucleotide of Exon 32 (c.3491_3627) which makes it likely to have some effect on normal mRNA splicing. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.17
CADD	Benign	22
DANN	Benign	0.94

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.27		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.27		Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1555120261; hg19: chr11-47354117;