18-3193914-A-C

Position:

• chr18-3193914-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_003803.4(MYOM1):​c.335T>G​(p.Leu112Trp) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYOM1 NM_003803.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 3.70

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]

ENSG00000265399 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.33743244).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYOM1	NM_003803.4	c.335T>G	p.Leu112Trp	missense_variant	3/38	ENST00000356443.9	NP_003794.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYOM1	ENST00000356443.9	c.335T>G	p.Leu112Trp	missense_variant	3/38	1	NM_003803.4	ENSP00000348821.4
MYOM1	ENST00000261606.11	c.335T>G	p.Leu112Trp	missense_variant	3/37	1		ENSP00000261606.7
ENSG00000265399	ENST00000580139.1	n.159A>C		non_coding_transcript_exon_variant	2/5	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 19, 2015

The p.Leu112Trp variant in MYOM1 has not been previously reported in individuals with cardiomyopathy or in large population studies. Computational prediction to ols and conservation analysis do not provide strong support for or against an im pact to the protein. In summary, the clinical significance of the p.Leu112Trp va riant is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Benign	-0.015	T
BayesDel_noAF	Benign	-0.26
CADD	Benign	22
DANN	Benign	0.95
DEOGEN2	Benign	0.13	T;.
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.21
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Benign	0.74	T;T
M_CAP	Benign	0.032	D
MetaRNN	Benign	0.34	T;T
MetaSVM	Benign	-0.84	T
MutationAssessor	Uncertain	2.2	M;M
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-2.2	N;N
REVEL	Benign	0.14
Sift	Uncertain	0.0010	D;D
Sift4G	Uncertain	0.018	D;D
Polyphen		0.99	D;D
Vest4		0.39
MutPred		0.24		Gain of MoRF binding (P = 0.0381);Gain of MoRF binding (P = 0.0381);
MVP		0.82
MPC		0.31
ClinPred		0.91	D
GERP RS		2.3
Varity_R		0.12
gMVP		0.68

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: rs868781965; hg19: chr18-3193912;