rs397516761

chr14-23390351-C-CT

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_002471.4(MYH6):c.3437_3438insA(p.Glu1147GlyfsTer86) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MYH6 NM_002471.4 frameshift
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 7.73

Genes affected

MYH6 (HGNC:7576): (myosin heavy chain 6) Cardiac muscle myosin is a hexamer consisting of two heavy chain subunits, two light chain subunits, and two regulatory subunits. This gene encodes the alpha heavy chain subunit of cardiac myosin. The gene is located approximately 4kb downstream of the gene encoding the beta heavy chain subunit of cardiac myosin. Mutations in this gene cause familial hypertrophic cardiomyopathy and atrial septal defect 3. [provided by RefSeq, Feb 2017]

ACMG classification

Verdict is Pathogenic. Variant got 10 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH6	NM_002471.4	c.3437_3438insA	p.Glu1147GlyfsTer86	frameshift_variant	26/39	ENST00000405093.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH6	ENST00000405093.9	c.3437_3438insA	p.Glu1147GlyfsTer86	frameshift_variant	26/39	5	NM_002471.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jul 03, 2014

The Glu1147fs variant in MYH6 has not been reported in any other families with c ardiomyopathy. Data from large population studies is insufficient to assess its frequency in the general population. This variant is predicted to cause a frames hift, which alters the protein?s amino acid sequence beginning at position 1147 and lead to a premature termination codon 86 amino acids downstream. This altera tion is then predicted to lead to a truncated or absent protein. Variants in MYH 6 have been reported in both individuals with in HCM and DCM (Carniel 2005, Hers hberger 2010), though its role in disease not yet well defined and it is unclear if a heterozygous loss-of-function variant would play a role in disease. In sum mary, the clinical significance of the Glu1147fs variant is uncertain. -

Hypertrophic cardiomyopathy 14 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 08, 2023

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. ClinVar contains an entry for this variant (Variation ID: 44485). This variant has not been reported in the literature in individuals affected with MYH6-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Glu1147Glyfs*86) in the MYH6 gene. It is expected to result in an absent or disrupted protein product. However, the current clinical and genetic evidence is not sufficient to establish whether loss-of-function variants in MYH6 cause disease. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Mar 28, 2018

- -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 03, 2023

The c.3437dupA variant, located in coding exon 24 of the MYH6 gene, results from a duplication of A at nucleotide position 3437, causing a translational frameshift with a predicted alternate stop codon (p.E1147Gfs*86). This alteration is expected to result in protein truncation or nonsense-mediated mRNA decay. However, loss of function of MYH6 has not been established as a mechanism of disease. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

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: rs397516761; hg19: chr14-23859560;