NM_000257.4:c.3346G>T

Variant names:

• chr14-23420225-C-A
• rs727504274
• NM_000257.4:c.3346G>T

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PVS1 PM2 PP3 PP5_Moderate

The NM_000257.4(MYH7):​c.3346G>T​(p.Glu1116*) variant causes a stop gained change involving the alteration of a 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 Likely pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MYH7 NM_000257.4 stop_gained
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.77
• Publications: 6 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: Pathogenic. The variant received 13 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 14-23420225-C-A is Pathogenic according to our data. Variant chr14-23420225-C-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3075740.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.3346G>T	p.Glu1116*	stop_gained	Exon 27 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.3346G>T	p.Glu1116*	stop_gained	Exon 26 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.3346G>T	p.Glu1116*	stop_gained	Exon 27 of 40	1	NM_000257.4	ENSP00000347507.3
MYH7	ENST00000713768.1	c.3346G>T	p.Glu1116*	stop_gained	Exon 27 of 41			ENSP00000519070.1
MYH7	ENST00000713769.1	c.3346G>T	p.Glu1116*	stop_gained	Exon 26 of 39			ENSP00000519071.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Data not reliable, filtered out with message: AC0;AS_VQSR AF: 0.00 AC: 0 AN: 1458034 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 725208

African (AFR) AF: 0.00 AC: 0 AN: 33444

American (AMR) AF: 0.00 AC: 0 AN: 44602

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26068

East Asian (EAS) AF: 0.00 AC: 0 AN: 39576

South Asian (SAS) AF: 0.00 AC: 0 AN: 85848

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 51362

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5696

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111136

Other (OTH) AF: 0.00 AC: 0 AN: 60302

GnomAD4 genome Cov.: 31

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiomyopathy Pathogenic:1

Feb 15, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Glu1116X variant in MYH7 has not been previously reported in individuals with hypertrophic cardiomyopathy (HCM) and was absent from large population studies. This nonsense variant leads to a premature termination codon at position 1116, which is predicted to lead to a truncated or absent protein. Although heterozygous loss-of-function (LOF) variants in MYH7, such as this variant, are not believed to be pathogenic for dominant forms of cardiomyopathy, there is evidence that can they lead to severe and early onset disease when present in trans with a second MYH7 variant (LMM data). In summary, although additional studies are required to fully establish its clinical significance, the p.Glu1116X variant is likely pathogenic. ACMG/AMP Criteria applied: PVS1, PM2. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.66
CADD	Pathogenic	48
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		7.8
Vest4		0.84
GERP RS		5.1
Mutation Taster		=9/191	disease causing (fs/PTC)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.70		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.70		Position offset: -3

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs727504274; hg19: chr14-23889434;