18-3129329-T-G

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 2P and 6B. PM2BP4_StrongBP6BP7

The NM_003803.4(MYOM1):​c.2697A>C​(p.Val899Val) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)

Consequence

MYOM1
NM_003803.4 synonymous

Scores

2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:2

Conservation

PhyloP100: 0.753
Variant links:
Genes affected
MYOM1 (HGNC:7613): (myomesin 1) The giant protein titin, together with its associated proteins, interconnects the major structure of sarcomeres, the M bands and Z discs. The C-terminal end of the titin string extends into the M line, where it binds tightly to M-band constituents of apparent molecular masses of 190 kD (myomesin 1) and 165 kD (myomesin 2). This protein, myomesin 1, like myomesin 2, titin, and other myofibrillar proteins contains structural modules with strong homology to either fibronectin type III (motif I) or immunoglobulin C2 (motif II) domains. Myomesin 1 and myomesin 2 each have a unique N-terminal region followed by 12 modules of motif I or motif II, in the arrangement II-II-I-I-I-I-I-II-II-II-II-II. The two proteins share 50% sequence identity in this repeat-containing region. The head structure formed by these 2 proteins on one end of the titin string extends into the center of the M band. The integrating structure of the sarcomere arises from muscle-specific members of the superfamily of immunoglobulin-like proteins. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.47).
BP6
Variant 18-3129329-T-G is Benign according to our data. Variant chr18-3129329-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 505378.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=1}.
BP7
Synonymous conserved (PhyloP=0.753 with no splicing effect.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
MYOM1NM_003803.4 linkc.2697A>C p.Val899Val synonymous_variant 18/38 ENST00000356443.9 NP_003794.3 P52179-1

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
MYOM1ENST00000356443.9 linkc.2697A>C p.Val899Val synonymous_variant 18/381 NM_003803.4 ENSP00000348821.4 P52179-1
MYOM1ENST00000261606.11 linkc.2506+2046A>C intron_variant 1 ENSP00000261606.7 P52179-2
MYOM1ENST00000582016.1 linkn.253A>C non_coding_transcript_exon_variant 1/34

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
Cov.:
31
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:1Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Benign:2
Likely benign, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineOct 25, 2016p.Val899Val in exon 18 of MYOM1: This variant is not expected to have clinical s ignificance because it does not alter an amino acid residue and is not located w ithin the splice consensus sequence. This variant was absent from large populati on studies. -
Likely benign, criteria provided, single submitterclinical testingAmbry GeneticsJun 18, 2024This 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. -
Hypertrophic cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpAug 31, 2024This sequence change affects codon 899 of the MYOM1 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MYOM1 protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MYOM1-related conditions. ClinVar contains an entry for this variant (Variation ID: 505378). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.47
CADD
Benign
12
DANN
Benign
0.76

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.090
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.

Other links and lift over

dbSNP: rs771666952; hg19: chr18-3129327; API