NM_000257.4:c.1826A>G

Variant names:

• chr14-23427647-T-C
• rs727504925
• NM_000257.4:c.1826A>G

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM1 PM2 PP2 PP3_Moderate PP5_Very_Strong

The NM_000257.4(MYH7):​c.1826A>G​(p.Tyr609Cys) 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 Likely pathogenic (★★).

• 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: 4.75

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 15 ACMG points.

• PM1: In a helix (size 7) in uniprot entity MYH7_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_000257.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the MYH7 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 341 curated pathogenic missense variants (we use a threshold of 10). The gene has 16 curated benign missense variants. Gene score misZ: 3.9329 (above the threshold of 3.09). Trascript score misZ: 6.7889 (above the threshold of 3.09). GenCC associations: The gene is linked to 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, 0.936
• PP5: Variant 14-23427647-T-C is Pathogenic according to our data. Variant chr14-23427647-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 179525.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr14-23427647-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.1826A>G	p.Tyr609Cys	missense_variant	Exon 16 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.1826A>G	p.Tyr609Cys	missense_variant	Exon 15 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.1826A>G	p.Tyr609Cys	missense_variant	Exon 16 of 40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:2

Apr 25, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces tyrosine, which is neutral and polar, with cysteine, which is neutral and slightly polar, at codon 609 of the MYH7 protein (p.Tyr609Cys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 21750094, 27247418, 31737537). ClinVar contains an entry for this variant (Variation ID: 179525). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MYH7 protein function with a positive predictive value of 95%. 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. -

Mar 07, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

proposed classification - variant undergoing re-assessment, contact laboratory -

not provided Pathogenic:1

Jul 16, 2023

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported in individuals with hypertrophic cardiomyopathy (HCM) from large cohort studies, but detailed clinical information and familial segregation information were not provided (Waldmuller et al., 2011; Homburger et al., 2016; Marschall et al., 2019; Harper et al., 2021); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 33495597, 31737537, 27247418, 21750094, 27532257, 29300372) -

Cardiovascular phenotype Pathogenic:1

Jun 16, 2022

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Y609C variant (also known as c.1826A>G), located in coding exon 14 of the MYH7 gene, results from an A to G substitution at nucleotide position 1826. The tyrosine at codon 609 is replaced by cysteine, an amino acid with highly dissimilar 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 variant has been reported in several hypertrophic cardiomyopathy (HCM) cases (Waldmüller S et al. Eur J Heart Fail, 2011 Nov;13:1185-92; Homburger JR et al. Proc Natl Acad Sci U S A, 2016 06;113:6701-6; Marschall C et al. Cardiovasc Diagn Ther, 2019 Oct;9:S292-S298; Harper AR et al. Nat Genet, 2021 02;53:135-142). 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	Uncertain	0.52
CardioboostCm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.32
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.87	D
Eigen	Uncertain	0.54
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.70	D
MutationAssessor	Uncertain	2.2	M
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-6.8	D
REVEL	Pathogenic	0.81
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0030	D
Polyphen		0.96	D
Vest4		0.97
MutPred		0.57		Gain of catalytic residue at L608 (P = 0.0017);
MVP		0.98
MPC		2.0
ClinPred		0.99	D
GERP RS		5.1
Varity_R		0.79
gMVP		0.94

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: rs727504925; hg19: chr14-23896856;