18-3135624-C-A

Position:

• chr18-3135624-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_003803.4(MYOM1):​c.2132G>T​(p.Arg711Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,096 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.

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 31)
• Consequence: MYOM1 NM_003803.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.91

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.941

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYOM1	NM_003803.4	c.2132G>T	p.Arg711Leu	missense_variant	15/38	ENST00000356443.9	NP_003794.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYOM1	ENST00000356443.9	c.2132G>T	p.Arg711Leu	missense_variant	15/38	1	NM_003803.4	ENSP00000348821.4
MYOM1	ENST00000261606.11	c.2132G>T	p.Arg711Leu	missense_variant	15/37	1		ENSP00000261606.7
MYOM1	ENST00000577294.1	n.188G>T		non_coding_transcript_exon_variant	2/2	2

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152096 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000241

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 Cov.: 30

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152096 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74290

Gnomad4 AFR AF: 0.0000241

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: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.87
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Benign	0.33	T;.;.
Eigen	Pathogenic	0.99
Eigen_PC	Pathogenic	0.94
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.94	D;D;D
MetaSVM	Uncertain	0.11	D
MutationAssessor	Pathogenic	3.3	M;.;M
PrimateAI	Uncertain	0.58	T
PROVEAN	Pathogenic	-6.5	D;.;D
REVEL	Pathogenic	0.75
Sift	Uncertain	0.0010	D;.;D
Sift4G	Uncertain	0.0020	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.96
MutPred		0.79		Loss of ubiquitination at K706 (P = 0.0821);.;Loss of ubiquitination at K706 (P = 0.0821);
MVP		0.92
MPC		0.69
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.73
gMVP		0.85

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.14		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: rs548747720; hg19: chr18-3135622;