NM_000258.3:c.520G>C

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1PM2PP2PP3

The NM_000258.3(MYL3):c.520G>C(p.Ala174Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,700 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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. A174V) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MYL3
NM_000258.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 3.18

Publications

0 publications found

Variant links:

Genes affected

MYL3 (HGNC:7584): (myosin light chain 3) MYL3 encodes myosin light chain 3, an alkali light chain also referred to in the literature as both the ventricular isoform and the slow skeletal muscle isoform. Mutations in MYL3 have been identified as a cause of mid-left ventricular chamber type hypertrophic cardiomyopathy. [provided by RefSeq, Jul 2008]

MYL3 Gene-Disease associations (from GenCC):

hypertrophic cardiomyopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
hypertrophic cardiomyopathy 8
Inheritance: AD, SD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
dilated cardiomyopathy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

MYL3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

PM1

In a chain Myosin light chain 3 (size 193) in uniprot entity MYL3_HUMAN there are 16 pathogenic changes around while only 6 benign (73%) in NM_000258.3

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 4 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 0.75572 (below the threshold of 3.09). Trascript score misZ: 1.3243 (below the threshold of 3.09). GenCC associations: The gene is linked to hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy 8.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.793

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL3	NM_000258.3 link	c.520G>C	p.Ala174Pro	missense_variant	Exon 5 of 7	ENST00000292327.6	NP_000249.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYL3	ENST00000292327.6 link	c.520G>C	p.Ala174Pro	missense_variant	Exon 5 of 7	1	NM_000258.3	ENSP00000292327.4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251086

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461700

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727140

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53242

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111998

Other (OTH)

AF:

0.00

AC:

AN:

60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0296732), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.400

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cardiomyopathy

Uncertain:2

Feb 28, 2023

Color Diagnostics, LLC DBA Color Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces alanine with proline at codon 174 of the MYL3 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with hypertrophic cardiomyopathy (PMID: 25611685, 27532257). This variant has been identified in 1/251086 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. -

Jun 13, 2023

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Oct 10, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Ala174Pro variant in MYL3 has not been previously reported in individuals with cardiomyopathy, but has been identified in 1/111520 of European chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; d bSNP rs397516279). Computational prediction tools and conservation analysis do n ot provide strong support for or against an impact to the protein. In summary, t he clinical significance of the p.Ala174Pro variant is uncertain. ACMG/AMP Crite ria applied: PM1 (Richards 2015). -

Hypertrophic cardiomyopathy

Uncertain:1

Apr 10, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.97

CardioboostCm

Uncertain

0.36

BayesDel_addAF

Uncertain

0.16

BayesDel_noAF

Uncertain

-0.010

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.74

D;D

Eigen

Uncertain

0.60

Eigen_PC

Uncertain

0.50

FATHMM_MKL

Uncertain

0.86

LIST_S2

Uncertain

0.97

.;D

M_CAP

Uncertain

0.17

MetaRNN

Pathogenic

0.79

D;D

MetaSVM

Uncertain

0.58

MutationAssessor

Pathogenic

3.7

H;H

PhyloP100

3.2

PrimateAI

Uncertain

0.65

PROVEAN

Uncertain

-3.1

D;D

REVEL

Uncertain

0.63

Sift

Uncertain

0.0060

D;D

Sift4G

Uncertain

0.060

T;T

Polyphen

0.99

D;D

Vest4

0.68

MutPred

0.35

Loss of catalytic residue at A174 (P = 0.0436);Loss of catalytic residue at A174 (P = 0.0436);

MVP

0.79

MPC

0.81

ClinPred

0.98

GERP RS

3.8

Varity_R

0.88

gMVP

0.75

Mutation Taster

=41/59

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over