14-23424068-C-T

Position:

• chr14-23424068-C-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000257.4(MYH7):​c.2761G>A​(p.Glu921Lys) 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E921A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 7.77

Genes affected

MYH7 (HGNC:7577): (myosin heavy chain 7) Muscle myosin is a hexameric protein containing 2 heavy chain subunits, 2 alkali light chain subunits, and 2 regulatory light chain subunits. This gene encodes the beta (or slow) heavy chain subunit of cardiac myosin. It is expressed predominantly in normal human ventricle. It is also expressed in skeletal muscle tissues rich in slow-twitch type I muscle fibers. Changes in the relative abundance of this protein and the alpha (or fast) heavy subunit of cardiac myosin correlate with the contractile velocity of cardiac muscle. Its expression is also altered during thyroid hormone depletion and hemodynamic overloading. Mutations in this gene are associated with familial hypertrophic cardiomyopathy, myosin storage myopathy, dilated cardiomyopathy, and Laing distal myopathy. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_000257.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MYH7. . Gene score misZ 3.9329 (greater than the threshold 3.09). Trascript score misZ 6.7889 (greater than threshold 3.09). GenCC has associacion of gene with hyaline body myopathy, MYH7-related skeletal myopathy, dilated cardiomyopathy 1S, congenital myopathy 7A, myosin storage, autosomal dominant, dilated cardiomyopathy, left ventricular noncompaction, myopathy, myosin storage, autosomal dominant, hypertrophic cardiomyopathy, congenital heart disease, Ebstein anomaly, arrhythmogenic right ventricular cardiomyopathy, myopathy, myosin storage, autosomal recessive, hypertrophic cardiomyopathy 1, familial isolated dilated cardiomyopathy.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979
• PP5: Variant 14-23424068-C-T is Pathogenic according to our data. Variant chr14-23424068-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 181205.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr14-23424068-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH7	NM_000257.4	c.2761G>A	p.Glu921Lys	missense_variant	23/40	ENST00000355349.4
MYH7	NM_001407004.1	c.2761G>A	p.Glu921Lys	missense_variant	22/39

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH7	ENST00000355349.4	c.2761G>A	p.Glu921Lys	missense_variant	23/40	1	NM_000257.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Dilated cardiomyopathy 1S Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Institute of Human Genetics, University of Leipzig Medical Center

Jan 01, 2019

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Oct 07, 2019

Identified in patients with HCM referred for genetic testing at GeneDx and in published literature (Van Driest et al., 2004; Santos et al., 2012; Viswanathan et al., 2017); Not observed in large population cohorts (Lek et al., 2016); Reported in ClinVar but additional evidence is not available (ClinVar Variant ID# 181205; Landrum et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 25961035, 22429680, 15358028, 29121657) -

Hypertrophic cardiomyopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 13, 2021

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, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has been observed in individuals affected with hypertrophic cardiomyopathy (PMID: 15358028, 22429680, 29121657). ClinVar contains an entry for this variant (Variation ID: 181205). This variant is not present in population databases (ExAC no frequency). This sequence change replaces glutamic acid with lysine at codon 921 of the MYH7 protein (p.Glu921Lys). The glutamic acid residue is highly conserved and there is a small physicochemical difference between glutamic acid and lysine. This variant is found within a region of MYH7 between codons 181 and 937 that contains the majority of the myosin head domain. Missense variants in this region have been shown to be significantly overrepresented in individuals with hypertrophic cardiomyopathy (PMID: 27532257). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 07, 2024

The p.E921K variant (also known as c.2761G>A), located in coding exon 21 of the MYH7 gene, results from a G to A substitution at nucleotide position 2761. The glutamic acid at codon 921 is replaced by lysine, an amino acid with similar properties. This alteration is located in the myosin head domain, which contains a statistically significant clustering of pathogenic missense variants (Homburger JR et al. Proc Natl Acad Sci U S A, 2016 06;113:6701-6; Walsh R et al. Genet Med, 2017 02;19:192-203; Ambry internal data). This alteration has been reported in multiple hypertrophic cardiomyopathy (HCM) cohorts and in individuals reported to have HCM (Van Driest SL et al. J Am Coll Cardiol, 2004 Aug;44:602-10; Santos S et al. BMC Med Genet, 2012 Mar;13:17; Viswanathan SK et al. PLoS One, 2017 Nov;12:e0187948; external communications; Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.88
CardioboostCm	Uncertain	0.89
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	28
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.83	D
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.92	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.93	D
MutationAssessor	Pathogenic	3.7	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.2	D
REVEL	Pathogenic	0.91
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0050	D
Polyphen		1.0	D
Vest4		0.92
MutPred		0.79		Gain of MoRF binding (P = 0.0076);
MVP		0.99
MPC		1.2
ClinPred		1.0	D
GERP RS		5.5
Varity_R		0.69
gMVP		0.99

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: rs730880759; hg19: chr14-23893277; COSMIC: COSV62518789;