rs11570112

Positions:

• chr11-47333924-G-A
• chr11-47333924-G-C

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000256.3(MYBPC3):​c.2992C>T​(p.Gln998*) variant causes a stop gained, splice region 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MYBPC3 NM_000256.3 stop_gained, splice_region
• Scores: Splicing: ADA: 0.9979
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 9.54

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 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-47333924-G-A is Pathogenic according to our data. Variant chr11-47333924-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 180993.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-47333924-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.2992C>T	p.Gln998*	stop_gained, splice_region_variant	28/35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.2992C>T	p.Gln998*	stop_gained, splice_region_variant	28/35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.2992C>T	p.Gln998*	stop_gained, splice_region_variant	27/34	5		ENSP00000382193.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Apr 21, 2014

This mutation is denoted p.Gln998Stop (CAG>TAG): c.2992 C>T in exon 28 of the MYBPC3 gene (NM_000256.3). The Q998X mutation in the MYBPC3 gene has been reported in at least one patient with HCM (Millat G et al., 2010). Millat et al. (2010) report that the Q998X mutation was not seen in 200 control individuals. Furthermore, the Q998X mutation was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Additionally, Q998X is predicted to cause loss of normal protein function either by protein truncation or nonsense-mediated mRNA decay. Other nonsense mutations in the MYBPC3 gene have been reported in association with HCM. In summary, Q998X in the MYBPC3 gene is interpreted as a disease-causing mutation. The variant is found in HCM panel(s). -

Hypertrophic cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 19, 2020

For these reasons, this variant has been classified as Pathogenic. Loss-of-function variants in MYBPC3 are known to be pathogenic (PMID: 19574547). This variant has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 20624503). ClinVar contains an entry for this variant (Variation ID: 180993). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Gln998*) in the MYBPC3 gene. It is expected to result in an absent or disrupted protein product. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 03, 2023

The p.Q998* pathogenic mutation (also known as c.2992C>T), located in coding exon 28 of the MYBPC3 gene, results from a C to T substitution at nucleotide position 2992. This changes the amino acid from a glutamine to a stop codon within coding exon 28. This alteration has been reported in hypertrophic cardiomyopathy cohorts and a sudden cardiac death cohort (Millat G et al. Eur J Med Genet, 2010 Jul;53:261-7; Helms AS et al. Circ Genom Precis Med, 2020 Oct;13:396-405; Guo L et al. JAMA Cardiol, 2021 Sep;6:1013-1022). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.61	D
BayesDel_noAF	Pathogenic	0.63
CADD	Pathogenic	53
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.87
FATHMM_MKL	Pathogenic	0.99	D
Vest4		0.93
GERP RS		4.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		0.37		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.37		Position offset: 34

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

Publications

LitVar

Other links and lift over

dbSNP: rs11570112; hg19: chr11-47355475;