14-23425364-G-T

Position:

• chr14-23425364-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The NM_000257.4(MYH7):​c.2341C>A​(p.Leu781Met) variant causes a missense change. 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. L781P) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 5.43

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a helix (size 20) in uniprot entity MYH7_HUMAN there are 22 pathogenic changes around while only 0 benign (100%) in NM_000257.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-23425363-A-G is described in Lovd as [Likely_pathogenic].
• 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, 0.927

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYH7	NM_000257.4	c.2341C>A	p.Leu781Met	missense_variant	21/40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.2341C>A	p.Leu781Met	missense_variant	20/39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.2341C>A	p.Leu781Met	missense_variant	21/40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 24, 2018

The p.L781M variant (also known as c.2341C>A), located in coding exon 19 of the MYH7 gene, results from a C to A substitution at nucleotide position 2341. The leucine at codon 781 is replaced by methionine, an amino acid with highly similar properties. This alteration has been detected once in a cohort of individuals with hypertrophic cardiomyopathy (HCM) (Wang J et al. Eur. J. Heart Fail., 2014 Sep;16:950-7). In addition, authors performed structural analysis on this alteration and determined that it impairs MYH7 lever arm compliance (Robert-Paganin J et al. Nat Commun, 2018 10;9:4019). A different alteration located at the same position, p.L781P, has also been detected in individuals with hypertrophic cardiomyopathy (Alfares AA et al. Genet. Med., 2015 Nov;17:880-8; 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. -

Hypertrophic cardiomyopathy 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

research

HudsonAlpha Institute for Biotechnology, HudsonAlpha Institute for Biotechnology

Mar 12, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.77
CardioboostCm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.18
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.45	T
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PrimateAI	Pathogenic	0.80	T
PROVEAN	Benign	-1.7	N
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.013	D
Polyphen		0.99	D
Vest4		0.89
MutPred		0.61		Gain of catalytic residue at L781 (P = 0.0227);
MVP		0.96
MPC		2.1
ClinPred		0.99	D
GERP RS		4.6
Varity_R		0.69
gMVP		0.96

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs1348730180; hg19: chr14-23894573;