rs397516274

Variant names:

• chr14-23430606-G-T
• rs397516274
• NM_000257.4:c.953C>A

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The NM_000257.4(MYH7):​c.953C>A​(p.Thr318Asn) variant causes a missense change involving the alteration of a non-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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T318P) 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:3
• Conservation: PhyloP100: 1.99
• Publications: 1 publications found

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]

MYH7 Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1S

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• MYH7-related skeletal myopathy

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• myopathy, myosin storage, autosomal recessive

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• myopathy, myosin storage, autosomal dominant

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• congenital myopathy 7A, myosin storage, autosomal dominant

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Ebstein anomaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hyaline body myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• left ventricular noncompaction

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• congenital heart disease

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 25 uncertain 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 chr14-23430607-T-G is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 619260.Status of the report is criteria_provided_single_submitter, 1 stars.
• 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 myopathy, myosin storage, autosomal recessive, MYH7-related skeletal myopathy, congenital myopathy 7A, myosin storage, autosomal dominant, Ebstein anomaly, hyaline body myopathy, left ventricular noncompaction, hypertrophic cardiomyopathy 1, dilated cardiomyopathy 1S, dilated cardiomyopathy, congenital heart disease, familial isolated dilated cardiomyopathy, myopathy, myosin storage, autosomal dominant, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.871

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.953C>A	p.Thr318Asn	missense_variant	Exon 11 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.953C>A	p.Thr318Asn	missense_variant	Exon 10 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.953C>A	p.Thr318Asn	missense_variant	Exon 11 of 40	1	NM_000257.4	ENSP00000347507.3
MYH7	ENST00000713768.1	c.953C>A	p.Thr318Asn	missense_variant	Exon 11 of 41			ENSP00000519070.1
MYH7	ENST00000713769.1	c.953C>A	p.Thr318Asn	missense_variant	Exon 10 of 39			ENSP00000519071.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:2

Jan 19, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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

May 16, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MYH7 c.953C>A (p.Thr318Asn) results in a non-conservative amino acid change located in the Myosin head, motor domain (IPR001609) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251392 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.953C>A has been reported in the literature in individuals affected with Hypertrophic Cardiomyopathy (Ho_2018). This report does not provide unequivocal conclusions about association of the variant with Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 30297972). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Hypertrophic cardiomyopathy Uncertain:1

Nov 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces threonine, which is neutral and polar, with asparagine, which is neutral and polar, at codon 318 of the MYH7 protein (p.Thr318Asn). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 27247418, 30297972; internal data). ClinVar contains an entry for this variant (Variation ID: 43112). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt MYH7 protein function with a positive predictive value of 95%. 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	Uncertain	0.41
CardioboostCm	Uncertain	0.43
BayesDel_addAF	Benign	-0.027	T
BayesDel_noAF	Benign	-0.28
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.86	D
Eigen	Benign	-0.34
Eigen_PC	Benign	-0.40
FATHMM_MKL	Uncertain	0.86	D
LIST_S2	Uncertain	0.95	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.87	D
MetaSVM	Uncertain	0.28	D
MutationAssessor	Benign	1.5	L
PhyloP100		2.0
PrimateAI	Uncertain	0.59	T
PROVEAN	Uncertain	-2.8	D
REVEL	Uncertain	0.33
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0030	D
Polyphen		0.28	B
Vest4		0.67
MutPred		0.42		Gain of catalytic residue at Q315 (P = 0.0226);
MVP		0.76
MPC		1.5
ClinPred		0.75	D
GERP RS		2.5
Varity_R		0.79
gMVP		0.75
Mutation Taster		=29/71	disease causing

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

Other links and lift over

dbSNP: rs397516274; hg19: chr14-23899815;