14-23412855-T-C

Variant names:

• chr14-23412855-T-C
• rs367543053
• NM_000257.4:c.5807A>G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PM4

The NM_000257.4(MYH7):​c.5807A>G​(p.Ter1936Trpext*?) variant causes a stop lost change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MYH7 NM_000257.4 stop_lost
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1 O:1
• Conservation: PhyloP100: 3.93

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 Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Stoplost variant in NM_000257.4 Downstream stopcodon found after 25 codons.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.5807A>G	p.Ter1936Trpext*?	stop_lost	Exon 40 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.5807A>G	p.Ter1936Trpext*?	stop_lost	Exon 39 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.5807A>G	p.Ter1936Trpext*?	stop_lost	Exon 40 of 40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

Myosin storage myopathy Pathogenic:1

Apr 01, 2011

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Hypertrophic cardiomyopathy Uncertain:1

Apr 29, 2018

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Two additional variants at this codon that result in the same elongation of the MYH7 protein (p.*1936Tyr*ext31 and p.*1936Leu*ext31) have been reported in individuals affected with MYH7-related myopathy (PMID: 27387980, 28927399). This suggests that variants that disrupt this residue are likely to be causative of disease. 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. This variant has been observed to segregate with congenital fiber type disproportion in a family (PMID: 21288719). ClinVar contains an entry for this variant (Variation ID: 42097). This variant is not present in population databases (ExAC no frequency). This sequence change disrupts the translational stop signal of the MYH7 mRNA. It is expected to extend the length of the MYH7 protein by 31 additional amino acid residues. -

Congenital myopathy with fiber type disproportion Other:1

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Benign	-0.063	T
BayesDel_noAF	Benign	-0.33
CADD	Benign	16
DANN	Benign	0.89
Eigen	Pathogenic	0.79
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Uncertain	0.81	D
Vest4		0.095
GERP RS		4.3

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: rs367543053; hg19: chr14-23882064;