rs117342470

chr18-3071880-C-Gchr18-3071880-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_003803.4(MYOM1):c.4718G>C(p.Arg1573Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000187 in 1,604,608 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. R1573Q) has been classified as Benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYOM1 NM_003803.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.66

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.878

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYOM1	NM_003803.4	c.4718G>C	p.Arg1573Pro	missense_variant	37/38	ENST00000356443.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYOM1	ENST00000356443.9	c.4718G>C	p.Arg1573Pro	missense_variant	37/38	1	NM_003803.4	P2
MYOM1	ENST00000261606.11	c.4430G>C	p.Arg1477Pro	missense_variant	36/37	1		A2
MYOM1	ENST00000581804.1	n.208G>C		non_coding_transcript_exon_variant	2/3	3

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152148 Hom.: 0 Cov.: 32

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: 0.00000138 AC: 2 AN: 1452460 Hom.: 0 Cov.: 30 AF XY: 0.00000277 AC XY: 2 AN XY: 721368

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: 0.00000181

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152148 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74310

Gnomad4 AFR AF: 0.00

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: 0.0000147

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 05, 2023

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MYOM1 protein function. ClinVar contains an entry for this variant (Variation ID: 1408130). This variant has not been reported in the literature in individuals affected with MYOM1-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.007%). This sequence change replaces arginine, which is basic and polar, with proline, which is neutral and non-polar, at codon 1573 of the MYOM1 protein (p.Arg1573Pro). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.29	D
BayesDel_noAF	Pathogenic	0.17
Cadd	Uncertain	26
Dann	Uncertain	1.0
DEOGEN2	Benign	0.25	T;.;.
Eigen	Uncertain	0.66
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.96	D;D;D
M_CAP	Uncertain	0.091	D
MetaRNN	Pathogenic	0.88	D;D;D
MetaSVM	Benign	-0.54	T
MutationAssessor	Uncertain	2.8	M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-5.4	D;.;D
REVEL	Uncertain	0.52
Sift	Uncertain	0.0020	D;.;D
Sift4G	Uncertain	0.0030	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.89
MutPred		0.66		Loss of MoRF binding (P = 0.0059);.;.;
MVP		0.75
MPC		0.75
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.95
gMVP		0.83

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

LitVar

Other links and lift over

dbSNP: rs117342470; hg19: chr18-3071878;