chr18-3116389-G-A

Position:

• chr18-3116389-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_003803.4(MYOM1):​c.3245C>T​(p.Ala1082Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,170 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. A1082G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• 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]

ACMG classification

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, 0.755

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYOM1	NM_003803.4	c.3245C>T	p.Ala1082Val	missense_variant	21/38	ENST00000356443.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYOM1	ENST00000356443.9	c.3245C>T	p.Ala1082Val	missense_variant	21/38	1	NM_003803.4	P2
MYOM1	ENST00000261606.11	c.2957C>T	p.Ala986Val	missense_variant	20/37	1		A2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461170 Hom.: 0 Cov.: 30 AF XY: 0.00000550 AC XY: 4 AN XY: 726858

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000360

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.29
BayesDel_addAF	Uncertain	0.049	T
BayesDel_noAF	Benign	-0.17
CADD	Uncertain	25
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.073	T;.;.
Eigen	Uncertain	0.66
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.87	D;D;D
M_CAP	Benign	0.037	D
MetaRNN	Pathogenic	0.76	D;D;D
MetaSVM	Benign	-0.64	T
MutationAssessor	Benign	2.0	M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.52	T
PROVEAN	Uncertain	-2.5	D;.;N
REVEL	Benign	0.19
Sift	Benign	0.055	T;.;T
Sift4G	Uncertain	0.010	D;D;D
Polyphen		1.0	D;.;D
Vest4		0.81
MutPred		0.41		Gain of methylation at K1081 (P = 0.0551);.;.;
MVP		0.90
MPC		0.55
ClinPred		0.98	D
GERP RS		5.3
Varity_R		0.28
gMVP		0.54

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: rs368707213; hg19: chr18-3116387;