chr14-23430583-C-T

Position:

chr14-23430583-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM5PP2

The NM_000257.4(MYH7):c.976G>A(p.Ala326Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000806 in 1,613,830 control chromosomes in the GnomAD database, with no homozygous occurrence. 15/22 in silico tools predict a benign 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. A326P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

MYH7
NM_000257.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: -0.488

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000257.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chr14-23430583-C-G is described in Lovd as [Pathogenic].

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MYH7. . Gene score misZ 3.9329 (greater than the threshold 3.09). Trascript score misZ 6.7889 (greater than threshold 3.09). GenCC has associacion of gene with 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH7	NM_000257.4 linkuse as main transcript	c.976G>A	p.Ala326Thr	missense_variant	11/40	ENST00000355349.4
MYH7	NM_001407004.1 linkuse as main transcript	c.976G>A	p.Ala326Thr	missense_variant	10/39

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH7	ENST00000355349.4 linkuse as main transcript	c.976G>A	p.Ala326Thr	missense_variant	11/40	1	NM_000257.4	P1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251204

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135766

show subpopulations

Gnomad AFR exome

AF:

0.0000616

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461664

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727128

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000630

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74352

show subpopulations

Gnomad4 AFR

AF:

0.0000724

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000453

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cardiomyopathy

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Dec 01, 2023	This missense variant replaces alanine with threonine at codon 326 of the MYH7 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two individuals affected with hypertrophic cardiomyopathy (PMID: 27532257). This variant has been identified in 1/251204 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 01, 2023	This missense variant replaces alanine with threonine at codon 326 of the MYH7 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two individuals affected with hypertrophic cardiomyopathy (PMID: 27532257). This variant has been identified in 1/251204 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Congenital myopathy with fiber type disproportion;C1834481:Dilated cardiomyopathy 1S;C1842160:Myosin storage myopathy;C1850709:Myopathy, myosin storage, autosomal recessive;C3495498:Hypertrophic cardiomyopathy 1;C4552004:MYH7-related skeletal myopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 22, 2021

- -

Hypertrophic cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 25, 2024

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 326 of the MYH7 protein (p.Ala326Thr). This variant is present in population databases (no rsID available, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with MYH7-related conditions. ClinVar contains an entry for this variant (Variation ID: 1332124). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MYH7 protein function. This variant is found within a region of MYH7 between codons 181 and 937 that contains the majority of the myosin head domain. Missense variants in this region have been shown to be significantly overrepresented in individuals with hypertrophic cardiomyopathy (PMID: 27532257). 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. -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 01, 2023

The p.A326T variant (also known as c.976G>A), located in coding exon 9 of the MYH7 gene, results from a G to A substitution at nucleotide position 976. The alanine at codon 326 is replaced by threonine, an amino acid with similar properties. This alteration has been reported in a hypertrophic cardiomyopathy (HCM) cohort (Homburger JR et al. Proc Natl Acad Sci U S A, 2016 Jun;113:6701-6). This alteration is located in the myosin head domain, which contains a statistically significant clustering of pathogenic missense variants (Homburger JR et al. Proc Natl Acad Sci U S A, 2016 06;113:6701-6; Walsh R et al. Genet Med, 2017 02;19:192-203; Ambry internal data). This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.078

CardioboostCm

Benign

0.073

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.37

CADD

Benign

9.3

DANN

Benign

0.91

DEOGEN2

Uncertain

0.67

Eigen

Benign

-1.1

Eigen_PC

Benign

-1.1

FATHMM_MKL

Benign

0.097

LIST_S2

Benign

0.79

M_CAP

Pathogenic

0.93

MetaRNN

Uncertain

0.65

MetaSVM

Uncertain

-0.27

MutationAssessor

Benign

1.3

MutationTaster

Benign

0.63

PrimateAI

Benign

0.30

PROVEAN

Benign

-1.2

REVEL

Benign

0.25

Sift

Benign

0.084

Sift4G

Benign

0.55

Polyphen

0.0010

Vest4

0.37

MutPred

0.57

Gain of catalytic residue at E328 (P = 0.034);

MVP

0.67

MPC

1.0

ClinPred

0.025

GERP RS

-3.0

Varity_R

0.13

gMVP

0.51

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over