rs199474816

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

5
9
6

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: ClinGen, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
  • 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

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

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MYL2NM_000432.4 linkc.58A>G p.Met20Val missense_variant Exon 2 of 7 ENST00000228841.15 NP_000423.2 P10916Q6IB42
MYL2NM_001406916.1 linkc.1A>G p.Met1? start_lost Exon 2 of 7 NP_001393845.1
MYL2NM_001406745.1 linkc.58A>G p.Met20Val missense_variant Exon 2 of 6 NP_001393674.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MYL2ENST00000228841.15 linkc.58A>G p.Met20Val missense_variant Exon 2 of 7 1 NM_000432.4 ENSP00000228841.8 P10916

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152132
Hom.:
0
Cov.:
32
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:
1
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:
4
AN:
1461692
Hom.:
0
Cov.:
30
AF XY:
0.00000275
AC XY:
2
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:
0
AN:
33478
American (AMR)
AF:
0.00
AC:
0
AN:
44720
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39700
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86220
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5636
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1112002
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60380
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000173), 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
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152132
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74304
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41434
American (AMR)
AF:
0.00
AC:
0
AN:
15266
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.000192
AC:
1
AN:
5198
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4818
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10604
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68018
Other (OTH)
AF:
0.00
AC:
0
AN:
2094
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<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:
1

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Hypertrophic cardiomyopathy 10 Uncertain:1
Jan 11, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces methionine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 20 of the MYL2 protein (p.Met20Val). This variant is present in population databases (rs199474816, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with MYL2-related conditions. ClinVar contains an entry for this variant (Variation ID: 919723). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. 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. -

Cardiomyopathy Uncertain:1
Mar 06, 2024
Color Diagnostics, LLC DBA Color Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This missense variant replaces methionine with valine at codon 20 of the MYL2 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 1/251468 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.33
CardioboostCm
Uncertain
0.79
BayesDel_addAF
Pathogenic
0.20
D
BayesDel_noAF
Pathogenic
0.14
CADD
Pathogenic
26
DANN
Uncertain
0.99
DEOGEN2
Uncertain
0.68
D;.
Eigen
Benign
0.18
Eigen_PC
Uncertain
0.32
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Benign
0.71
T;T
M_CAP
Pathogenic
0.43
D
MetaRNN
Pathogenic
0.84
D;D
MetaSVM
Uncertain
-0.21
T
MutationAssessor
Benign
1.9
L;.
PhyloP100
7.6
PrimateAI
Uncertain
0.63
T
PROVEAN
Uncertain
-3.0
D;D
REVEL
Pathogenic
0.70
Sift
Uncertain
0.0030
D;D
Sift4G
Benign
0.079
T;D
Polyphen
0.013
B;.
Vest4
0.79
MutPred
0.53
Gain of catalytic residue at N16 (P = 0.0126);Gain of catalytic residue at N16 (P = 0.0126);
MVP
0.83
MPC
0.48
ClinPred
0.89
D
GERP RS
5.3
Varity_R
0.89
gMVP
0.81
Mutation Taster
=36/64
disease causing

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

Other links and lift over

dbSNP: rs199474816; hg19: chr12-111356943; API