12-110915783-G-A

Variant names:

• chr12-110915783-G-A
• rs876657894
• NM_000432.4:c.101C>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PP2 PP3

The NM_000432.4(MYL2):​c.101C>T​(p.Thr34Ile) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000743 in 1,614,050 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. T34N) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000075 (0 hom.)
• Consequence: MYL2 NM_000432.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.60
• Publications: 0 publications found

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

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_000432.4
• 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, 0.835

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL2	NM_000432.4	c.101C>T	p.Thr34Ile	missense_variant	Exon 3 of 7	ENST00000228841.15	NP_000423.2
MYL2	NM_001406916.1	c.44C>T	p.Thr15Ile	missense_variant	Exon 3 of 7		NP_001393845.1
MYL2	NM_001406745.1	c.94-1459C>T		intron_variant	Intron 2 of 5		NP_001393674.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYL2	ENST00000228841.15	c.101C>T	p.Thr34Ile	missense_variant	Exon 3 of 7	1	NM_000432.4	ENSP00000228841.8

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152212 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000752 AC: 11 AN: 1461838 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 727224

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000989 AC: 11 AN: 1111972

Other (OTH) AF: 0.00 AC: 0 AN: 60388

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152212 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74352

African (AFR) AF: 0.00 AC: 0 AN: 41460

American (AMR) AF: 0.00 AC: 0 AN: 15282

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68042

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Mar 30, 2021

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Thr34Ile variant in MYL2 has not been previously reported in individuals with cardiomyopathy and was absent from large population studies. Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. In summary, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM2_Supporting. -

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 threonine with isoleucine at codon 34 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). 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 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
CardioboostCm	Uncertain	0.83
BayesDel_addAF	Pathogenic	0.17	D
BayesDel_noAF	Uncertain	0.0
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D
Eigen	Uncertain	0.66
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D
M_CAP	Uncertain	0.095	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Uncertain	2.1	M
PhyloP100		9.6
PrimateAI	Pathogenic	0.81	D
PROVEAN	Pathogenic	-4.4	D
REVEL	Uncertain	0.47
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.033	D
Polyphen		0.71	P
Vest4		0.72
MutPred		0.45		Gain of catalytic residue at D37 (P = 0.0068);
MVP		0.91
MPC		0.99
ClinPred		0.99	D
GERP RS		5.1
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

Other links and lift over

dbSNP: rs876657894; hg19: chr12-111353587;