rs28933098

Positions:

• chr14-23415021-G-A
• chr14-23415021-G-T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5

The NM_000257.4(MYH7):​c.5533C>T​(p.Arg1845Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,457,642 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1845Q) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:6 U:1
• Conservation: PhyloP100: 0.538

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 12 ACMG points.

• PM1: In a turn (size 3) in uniprot entity MYH7_HUMAN there are 5 pathogenic changes around while only 1 benign (83%) 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 chr14-23415020-C-T is described in ClinVar as [Uncertain_significance]. Clinvar id is 181286.Status of the report is reviewed_by_expert_panel, 3 stars. We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=4, Likely_pathogenic=2}.
• PP2: Missense variant where missense usually causes diseases, MYH7
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.964
• PP5: Variant 14-23415021-G-A is Pathogenic according to our data. Variant chr14-23415021-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 14114.We mark this variant Likely_pathogenic, oryginal submissions are: {Pathogenic=4, Likely_pathogenic=1, Uncertain_significance=1}. Variant chr14-23415021-G-A is described in Lovd as [Pathogenic]. Variant chr14-23415021-G-A is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH7	NM_000257.4	c.5533C>T	p.Arg1845Trp	missense_variant	37/40	ENST00000355349.4
MYH7	NM_001407004.1	c.5533C>T	p.Arg1845Trp	missense_variant	36/39

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH7	ENST00000355349.4	c.5533C>T	p.Arg1845Trp	missense_variant	37/40	1	NM_000257.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1457642 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 725400

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: 0.0000406

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:6 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Myosin storage myopathy Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	MGZ Medical Genetics Center	Oct 19, 2021	- -
Pathogenic, no assertion criteria provided	literature only	OMIM	Apr 14, 2009	- -

not provided Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jun 01, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Oct 26, 2022	- -

Hyaline body myopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 24, 2020

The p.Arg1845Trp variant in MYH7 has been reported in at least 10 individuals with myosin storage myopathy and segregated with disease in at least 10 affected family members from at least three families (Tajsharghi 2003, Laing 2005, Shingde 2006, Pegoraro 2007, Kiphuth 2010, Harris 2017, Li 2018). This variant was absent from large population studies, but has been reported in ClinVar (Variation ID: 14114). Computational prediction tools and conservation analyses are consistent with pathogenicity. In vitro and in vivo functional studies support an impact on protein function (Armel 2009, Dahl-Halvarsson 2017, Viswanathan 2017). In summary, this variant meets criteria to be classified as pathogenic for autosomal dominant myosin storage myopathy. ACMG/AMP Criteria applied: PP1_Strong, PM2, PS3_Moderate, PS4_Moderate, PP3. -

Hypertrophic cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Mar 31, 2023

For these reasons, this variant has been classified as Pathogenic. Experimental studies have shown that this missense change affects MYH7 function (PMID: 19336582). 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. ClinVar contains an entry for this variant (Variation ID: 14114). This missense change has been observed in individuals with myosin storage myopathy and skeletal myopathy (PMID: 14520662, 15699387, 17118657, 17336526, 20376763). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with tryptophan, which is neutral and slightly polar, at codon 1845 of the MYH7 protein (p.Arg1845Trp). -

Cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Apr 08, 2022

This missense variant replaces arginine with tryptophan at codon 1845 in the LMM domain of the MYH7 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown that this variant disrupts myosin filament assembly (PMID: 19336582, 28125727, 28973424) and impairs jump and flight ability in Drosophila mutants (PMID: 28973424, 33234710). This variant has been reported in multiple families and individuals affected with myosin-related disorders without cardiac involvement, including myosin storage myopathy (PMID: 14520662, 15699387, 17118657, 17336526, 20376763), scapulo-peroneal myopathy (PMID: 17336526), hereditary myopathy (PMID: 29170849), and inherited muscle disease (PMID: 31791368). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). In summary, while this variant has been reported to cause myosin storage myopathy, the additional evidence is insufficient to determine the role of this variant in cardiomyopathy conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
CardioboostCm	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.40	D
BayesDel_noAF	Pathogenic	0.34
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Pathogenic	4.3	H
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.82
MVP		0.98
MPC		1.6
ClinPred		1.0	D
GERP RS		4.5
Varity_R		0.55
gMVP		0.85

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: rs28933098; hg19: chr14-23884230; COSMIC: COSV62517164; COSMIC: COSV62517164;