rs1555123639

Variant names:

• chr11-47350612-T-G
• rs1555123639
• NM_000256.3:c.296A>C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000256.3(MYBPC3):​c.296A>C​(p.Lys99Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000149 in 1,341,012 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000015 (1 hom.)
• Consequence: MYBPC3 NM_000256.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.253

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.10301229).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.296A>C	p.Lys99Thr	missense_variant	Exon 3 of 35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.296A>C	p.Lys99Thr	missense_variant	Exon 3 of 35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.296A>C	p.Lys99Thr	missense_variant	Exon 3 of 34	5		ENSP00000382193.2
MYBPC3	ENST00000544791.1	n.296A>C		non_coding_transcript_exon_variant	Exon 3 of 27	5		ENSP00000444259.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000201 AC: 2 AN: 99426 Hom.: 1 AF XY: 0.0000364 AC XY: 2 AN XY: 54898

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000472

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000149 AC: 2 AN: 1341012 Hom.: 1 Cov.: 31 AF XY: 0.00000303 AC XY: 2 AN XY: 660896

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000188

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Jan 11, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Lys99Thr variant in MYBPC3 has not been previously reported in individuals with cardiomyopathy. Data from large population studies is insufficient to asse ss the frequency of this variant. This variant was predicted to be benign using a computational tool clinically validated by our laboratory. This tool's benign prediction is estimated to be correct 89% of the time (Jordan 2011). In summary , the clinical significance of the p.Lys99Thr variant is uncertain. -

Hypertrophic cardiomyopathy Uncertain:1

Nov 26, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine with threonine at codon 99 of the MYBPC3 protein (p.Lys99Thr). The lysine residue is moderately conserved and there is a moderate physicochemical difference between lysine and threonine. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals with MYBPC3-related conditions. ClinVar contains an entry for this variant (Variation ID: 517237). 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 tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
CardioboostCm	Benign	0.0030
BayesDel_addAF	Benign	-0.073	T
BayesDel_noAF	Benign	-0.34
CADD	Benign	18
DANN	Uncertain	0.98
DEOGEN2	Benign	0.34	T;T;T
Eigen	Benign	-0.59
Eigen_PC	Benign	-0.47
FATHMM_MKL	Uncertain	0.80	D
LIST_S2	Benign	0.74	T;T;T
M_CAP	Benign	0.047	D
MetaRNN	Benign	0.10	T;T;T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	0.0	N;.;.
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-2.2	N;N;N
REVEL	Benign	0.051
Sift	Uncertain	0.021	D;D;D
Sift4G	Benign	0.14	T;T;T
Polyphen		0.016	B;.;.
Vest4		0.28
MutPred		0.34		Loss of ubiquitination at K99 (P = 0.0056);Loss of ubiquitination at K99 (P = 0.0056);Loss of ubiquitination at K99 (P = 0.0056);
MVP		0.66
MPC		0.33
ClinPred		0.067	T
GERP RS		2.3
Varity_R		0.14
gMVP		0.42

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs1555123639; hg19: chr11-47372163;