14-23424846-C-T

Variant names:

• chr14-23424846-C-T
• NM_000257.4:c.2602G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP5_Moderate

The NM_000257.4(MYH7):​c.2602G>A​(p.Ala868Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. A868P) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.11

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 120) in uniprot entity MYH7_HUMAN there are 91 pathogenic changes around while only 3 benign (97%) 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 chr14-23424846-C-G is described in Lovd as [Pathogenic].
• 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.
• PP5: Variant 14-23424846-C-T is Pathogenic according to our data. Variant chr14-23424846-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2803488.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.2602G>A	p.Ala868Thr	missense_variant	Exon 22 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.2602G>A	p.Ala868Thr	missense_variant	Exon 21 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.2602G>A	p.Ala868Thr	missense_variant	Exon 22 of 40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:1

Apr 25, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with MYH7-related conditions. This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 868 of the MYH7 protein (p.Ala868Thr). This variant is not present in population databases (gnomAD no frequency). 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. This variant disrupts the p.Ala868 amino acid residue in MYH7. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 20624503, 27532257; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.059
CardioboostCm	Uncertain	0.52
BayesDel_addAF	Uncertain	0.16	D
BayesDel_noAF	Uncertain	-0.010
CADD	Benign	21
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.83	D
Eigen	Benign	-0.022
Eigen_PC	Benign	0.080
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.85	T
M_CAP	Pathogenic	0.54	D
MetaRNN	Uncertain	0.56	D
MetaSVM	Uncertain	0.45	D
MutationAssessor	Uncertain	2.3	M
PrimateAI	Uncertain	0.66	T
PROVEAN	Benign	-2.3	N
REVEL	Uncertain	0.54
Sift	Benign	0.032	D
Sift4G	Benign	0.25	T
Polyphen		0.0060	B
Vest4		0.34
MutPred		0.39		Gain of phosphorylation at A868 (P = 0.0046);
MVP		0.95
MPC		1.1
ClinPred		0.80	D
GERP RS		3.8
Varity_R		0.24
gMVP		0.96

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

No publications associated with this variant yet.

Other links and lift over

hg19: chr14-23894055;