Genetic Variant NM_003803.4:c.2062A>G (chr18-3135694-T-C) – ACMG Classification: Uncertain_significance (3 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3

The NM_003803.4(MYOM1):c.2062A>G(p.Thr688Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,678 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T688S) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 31)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MYOM1
NM_003803.4 missense

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 6.21

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 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.776

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYOM1	NM_003803.4 link	c.2062A>G	p.Thr688Ala	missense_variant	Exon 15 of 38	ENST00000356443.9	NP_003794.3	P52179-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
MYOM1	ENST00000356443.9 link	c.2062A>G	p.Thr688Ala	missense_variant	Exon 15 of 38	1	NM_003803.4	ENSP00000348821.4	P52179-1
MYOM1	ENST00000261606.11 link	c.2062A>G	p.Thr688Ala	missense_variant	Exon 15 of 37	1		ENSP00000261606.7	P52179-2
MYOM1	ENST00000577294.1 link	n.118A>G		non_coding_transcript_exon_variant	Exon 2 of 2	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461678

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727122

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

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.19

BayesDel_addAF

Uncertain

0.056

BayesDel_noAF

Benign

-0.16

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Benign

0.058

T;.;.

Eigen

Uncertain

0.53

Eigen_PC

Uncertain

0.58

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.84

T;D;D

M_CAP

Benign

0.022

MetaRNN

Pathogenic

0.78

D;D;D

MetaSVM

Benign

-0.82

MutationAssessor

Benign

1.4

L;.;L

PrimateAI

Uncertain

0.54

PROVEAN

Benign

-2.3

N;.;N

REVEL

Benign

0.18

Sift

Benign

0.22

T;.;T

Sift4G

Benign

0.42

T;T;T

Polyphen

0.99

D;.;D

Vest4

0.76

MutPred

0.41

Loss of methylation at K693 (P = 0.0704);.;Loss of methylation at K693 (P = 0.0704);

MVP

0.84

MPC

0.52

ClinPred

0.97

GERP RS

5.8

Varity_R

0.25

gMVP

0.50

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

No publications associated with this variant yet.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over