chr18-3094171-G-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_003803.4(MYOM1):c.3863C>T(p.Pro1288Leu) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000614 in 1,613,592 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P1288P) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00015 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000052 ( 0 hom. )

Consequence

MYOM1
NM_003803.4 missense, splice_region

Scores

Splicing: ADA: 0.8056

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 3.05

Publications

4 publications found

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]

MYOM1 Gene-Disease associations (from GenCC):

hypertrophic cardiomyopathy
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

MYOM1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.18953547).

BS2

High AC in GnomAd4 at 23 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_003803.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYOM1	NM_003803.4	MANE Select	c.3863C>T	p.Pro1288Leu	missense splice_region	Exon 26 of 38	NP_003794.3
	MYOM1	NM_019856.2		c.3575C>T	p.Pro1192Leu	missense splice_region	Exon 25 of 37	NP_062830.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYOM1	ENST00000356443.9	TSL:1 MANE Select	c.3863C>T	p.Pro1288Leu	missense splice_region	Exon 26 of 38	ENSP00000348821.4
	MYOM1	ENST00000261606.11	TSL:1	c.3575C>T	p.Pro1192Leu	missense splice_region	Exon 25 of 37	ENSP00000261606.7

Frequencies

GnomAD3 genomes

AF:

0.000151

AC:

AN:

152048

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000531

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

GnomAD2 exomes

AF:

0.0000602

AC:

AN:

249094

AF XY:

0.0000666

show subpopulations

Gnomad AFR exome

AF:

0.000517

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000557

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000354

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000520

AC:

AN:

1461544

Hom.:

Cov.:

AF XY:

0.0000426

AC XY:

AN XY:

727062

show subpopulations

African (AFR)

AF:

0.000568

AC:

AN:

33476

American (AMR)

AF:

0.0000447

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39694

South Asian (SAS)

AF:

0.00

AC:

AN:

86234

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53388

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000459

AC:

AN:

1111770

Other (OTH)

AF:

0.0000663

AC:

AN:

60372

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.478

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.000151

AC:

AN:

152048

Hom.:

Cov.:

AF XY:

0.000108

AC XY:

AN XY:

74244

show subpopulations

African (AFR)

AF:

0.000531

AC:

AN:

41418

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5194

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10550

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68002

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.492

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

Alfa

AF:

0.0000883

Hom.:

Bravo

AF:

0.000185

ESP6500AA

AF:

0.000276

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000662

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Jun 16, 2016

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Pro1288Leu variant in MYOM1 has not been previously reported in individual s with cardiomyopathy, but has been identified in 5/9782 African chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs 200808890). Computational prediction tools and conservation analysis suggest tha t the p.Pro1288Leu variant may impact the protein, though this information is no t predictive enough to determine pathogenicity. This variant is located in the l ast three bases of the exon, which is part of the 5? splice region. Computationa l tools do not suggest an impact to splicing. However, this information is not p redictive enough to rule out pathogenicity. In summary, the clinical significanc e of the p.Pro1288Leu variant is uncertain.

Aug 06, 2025

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.P1288L variant (also known as c.3863C>T), located in coding exon 25 of the MYOM1 gene, results from a C to T substitution at nucleotide position 3863. The proline at codon 1288 is replaced by leucine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear.

Hypertrophic cardiomyopathy

Uncertain:1

Nov 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 1288 of the MYOM1 protein (p.Pro1288Leu). This variant is present in population databases (rs200808890, gnomAD 0.05%). 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: 504857). 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.

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.44

BayesDel_addAF

Benign

-0.39

BayesDel_noAF

Benign

-0.46

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.23

Eigen

Uncertain

0.30

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Uncertain

0.89

LIST_S2

Uncertain

0.95

M_CAP

Benign

0.012

MetaRNN

Benign

0.19

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.7

PhyloP100

3.0

PrimateAI

Uncertain

0.49

PROVEAN

Uncertain

-4.3

REVEL

Benign

0.059

Sift

Uncertain

0.0070

Sift4G

Uncertain

0.018

Polyphen

0.97

Vest4

0.33

MVP

0.63

MPC

0.32

ClinPred

0.31

GERP RS

4.7

Varity_R

0.34

gMVP

0.36

Mutation Taster

=76/24

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.81

dbscSNV1_RF

Benign

0.52

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

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over