Genetic Variant NM_000432.4:c.58A>G (chr12-110919139-T-C) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

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

The NM_000432.4(MYL2):c.58A>G(p.Met20Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,824 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. M20L) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

MYL2
NM_000432.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 7.64

Publications

5 publications found

Variant links:

Genes affected

MYL2 (HGNC:7583): (myosin light chain 2) This gene encodes a major sarcomeric protein in mammalian striated muscle. The encoded protein plays a role in embryonic heart muscle structure and function, while phosphorylation of the encoded protein is involved in cardiac myosin cycling kinetics, torsion and function in adults. Mutations in this gene are associated with hypertrophic cardiomyopathy 10 and infant-onset myopathy. [provided by RefSeq, May 2022]

MYL2 Gene-Disease associations (from GenCC):

hypertrophic cardiomyopathy
Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
hypertrophic cardiomyopathy 10
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
myopathy, myofibrillar, 12, infantile-onset, with cardiomyopathy
Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics
congenital fiber-type disproportion myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
dilated cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

MYL2 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 hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 29 uncertain in NM_000432.4

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 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 0.39564 (below the threshold of 3.09). Trascript score misZ: 1.1124 (below the threshold of 3.09). GenCC associations: The gene is linked to hypertrophic cardiomyopathy 10, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, myopathy, myofibrillar, 12, infantile-onset, with cardiomyopathy, congenital fiber-type disproportion myopathy.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.838

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000432.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MYL2	NM_000432.4	MANE Select	c.58A>G	p.Met20Val	missense	Exon 2 of 7	NP_000423.2	P10916
MYL2	NM_001406916.1		c.1A>G	p.Met1?	start_lost	Exon 2 of 7	NP_001393845.1	A0A590UJU8
MYL2	NM_001406745.1		c.58A>G	p.Met20Val	missense	Exon 2 of 6	NP_001393674.1	G3V1V8

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MYL2	ENST00000228841.15	TSL:1 MANE Select	c.58A>G	p.Met20Val	missense	Exon 2 of 7	ENSP00000228841.8	P10916
MYL2	ENST00000663220.1		c.1A>G	p.Met1?	start_lost	Exon 2 of 7	ENSP00000499568.1	A0A590UJU8
MYL2	ENST00000713800.1		c.58A>G	p.Met20Val	missense	Exon 3 of 8	ENSP00000519106.1	P10916

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152132

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000192

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

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251468

AF XY:

0.00000736

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461692

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727118

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:

33478

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86220

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5636

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1112002

Other (OTH)

AF:

0.0000166

AC:

AN:

60380

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000173310), 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

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152132

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74304

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41434

American (AMR)

AF:

0.00

AC:

AN:

15266

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000192

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10604

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68018

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome 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

ExAC

AF:

0.00000824

AC:

ClinVar

ClinVar submissions

Significance:Uncertain significance

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Cardiomyopathy (1)

Hypertrophic cardiomyopathy 10 (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.33

CardioboostCm

Uncertain

0.79

BayesDel_addAF

Pathogenic

0.20

BayesDel_noAF

Pathogenic

0.14

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.68

Eigen

Benign

0.18

Eigen_PC

Uncertain

0.32

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.71

M_CAP

Pathogenic

0.43

MetaRNN

Pathogenic

0.84

MetaSVM

Uncertain

-0.21

MutationAssessor

Benign

1.9

PhyloP100

7.6

PrimateAI

Uncertain

0.63

PROVEAN

Uncertain

-3.0

REVEL

Pathogenic

0.70

Sift

Uncertain

0.0030

Sift4G

Benign

0.079

Polyphen

0.013

Vest4

0.79

MutPred

0.53

Gain of catalytic residue at N16 (P = 0.0126)

MVP

0.83

MPC

0.48

ClinPred

0.89

GERP RS

5.3

Varity_R

0.89

gMVP

0.81

Mutation Taster

=36/64

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over