Genetic Variant MYL2:p.Ala55Ser (chr12-110915721-C-A) – ACMG Classification: Uncertain_significance (4 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PM2

The NM_000432.4(MYL2):c.163G>T(p.Ala55Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,962 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MYL2
NM_000432.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3B:1

Conservation

PhyloP100: 7.57

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 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM1

In a domain EF-hand 1 (size 35) in uniprot entity MLRV_HUMAN there are 7 pathogenic changes around while only 0 benign (100%) in NM_000432.4

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL2	NM_000432.4 link	c.163G>T	p.Ala55Ser	missense_variant	Exon 3 of 7	ENST00000228841.15	NP_000423.2	P10916Q6IB42
MYL2	NM_001406916.1 link	c.106G>T	p.Ala36Ser	missense_variant	Exon 3 of 7		NP_001393845.1
MYL2	NM_001406745.1 link	c.94-1397G>T		intron_variant	Intron 2 of 5		NP_001393674.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
MYL2	ENST00000228841.15 link	c.163G>T	p.Ala55Ser	missense_variant	Exon 3 of 7	1	NM_000432.4	ENSP00000228841.8	P10916
MYL2	ENST00000663220.1 link	c.106G>T	p.Ala36Ser	missense_variant	Exon 3 of 7			ENSP00000499568.1	A0A590UJU8
MYL2	ENST00000548438.1 link	c.94-1397G>T		intron_variant	Intron 2 of 5	3		ENSP00000447154.1	G3V1V8

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461796

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727206

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74340

show subpopulations

Gnomad4 AFR

AF:

0.0000483

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

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000378

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1Uncertain:3Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Hypertrophic cardiomyopathy

Uncertain:2

May 04, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with serine at codon 55 of the MYL2 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 an individual affected with hypertrophic cardiomyopathy (PMID: 27532257). This variant has not been identified 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. -

Apr 05, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Disclaimer: This variant has not undergone full assessment. The following are preliminary notes: Not reported in affected people. Seen in one person with HCM at the LMM. Not in Gnomad. Clinvar: LP (GeneDx - 2015). -

not provided

Pathogenic:1

Apr 01, 2015

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The A55S variant has not been published as a pathogenic variant, nor has it been reported as a benign polymorphism to our knowledge. The A55S variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The A55S variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. This substitution occurs at a position that is conserved across species. Additionally, missense variants in nearby residues (N47K, G57E, R58N) have been reported in the Human Gene Mutation Database in association with HCM (Stenson et al., 2014), supporting the functional importance of this region of the protein. Nevertheless, in silico analysis is inconsistent in its predictions as to whether or not the variant is damaging to the protein structure/function.Therefore, this variant is a strong candidate for a pathogenic variant, however the possibility that it is a benign variant cannot be excluded. -

Hypertrophic cardiomyopathy 10

Uncertain:1

Nov 10, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 55 of the MYL2 protein (p.Ala55Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 27532257, 37652022). ClinVar contains an entry for this variant (Variation ID: 177958). 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 disruptive. 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

Benign:1

Feb 22, 2024

Ambry Genetics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

CardioboostCm

Benign

0.016

BayesDel_addAF

Benign

-0.10

BayesDel_noAF

Benign

-0.38

CADD

Uncertain

DANN

Benign

0.97

DEOGEN2

Benign

0.22

Eigen

Benign

-0.33

Eigen_PC

Benign

-0.14

FATHMM_MKL

Uncertain

0.97

LIST_S2

Benign

0.81

M_CAP

Uncertain

0.099

MetaRNN

Uncertain

0.50

MetaSVM

Benign

-0.90

MutationAssessor

Benign

-0.65

PrimateAI

Uncertain

0.73

PROVEAN

Benign

0.33

REVEL

Benign

0.26

Sift

Benign

1.0

Sift4G

Benign

1.0

Polyphen

0.069

Vest4

0.65

MVP

0.75

MPC

0.79

ClinPred

0.88

GERP RS

5.1

Varity_R

0.52

gMVP

0.69

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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