18-3116343-G-A

Position:

• chr18-3116343-G-A

Variant summary

Our verdict is Benign. Variant got -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BP7 BS2

The NM_003803.4(MYOM1):​c.3291C>T​(p.Asn1097=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00098 in 1,611,152 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00049 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0010 (2 hom.)
• Consequence: MYOM1 NM_003803.4 synonymous
• Clinical Significance: Likely benign criteria provided, multiple submitters, no conflicts B:2
• Conservation: PhyloP100: 0.850

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 Benign. Variant got -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.52).
• BP6: Variant 18-3116343-G-A is Benign according to our data. Variant chr18-3116343-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 416027.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=0.85 with no splicing effect.
• BS2: High Homozygotes in GnomAdExome4 at 2 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYOM1	NM_003803.4	c.3291C>T	p.Asn1097=	synonymous_variant	21/38	ENST00000356443.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYOM1	ENST00000356443.9	c.3291C>T	p.Asn1097=	synonymous_variant	21/38	1	NM_003803.4	P2
MYOM1	ENST00000261606.11	c.3003C>T	p.Asn1001=	synonymous_variant	20/37	1		A2

Frequencies

GnomAD3 genomes AF: 0.000493 AC: 75 AN: 152166 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000410

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: 0.0000942

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000823

Gnomad OTH AF: 0.000478

GnomAD3 exomes AF: 0.000385 AC: 95 AN: 246554 Hom.: 1 AF XY: 0.000441 AC XY: 59 AN XY: 133834

Gnomad AFR exome AF: 0.000392

Gnomad AMR exome AF: 0.0000292

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000561

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.000374

Gnomad NFE exome AF: 0.000672

Gnomad OTH exome AF: 0.000667

GnomAD4 exome AF: 0.00103 AC: 1504 AN: 1458986 Hom.: 2 Cov.: 30 AF XY: 0.00103 AC XY: 747 AN XY: 725672

Gnomad4 AFR exome AF: 0.000240

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.000375

Gnomad4 NFE exome AF: 0.00130

Gnomad4 OTH exome AF: 0.000532

GnomAD4 genome AF: 0.000493 AC: 75 AN: 152166 Hom.: 0 Cov.: 32 AF XY: 0.000377 AC XY: 28 AN XY: 74342

Gnomad4 AFR AF: 0.000410

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000942

Gnomad4 NFE AF: 0.000823

Gnomad4 OTH AF: 0.000478

Alfa AF: 0.000638 Hom.: 0

Bravo AF: 0.000457

ClinVar

Significance: Likely benign

Submissions summary: Benign:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

May 11, 2022

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Hypertrophic cardiomyopathy Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 24, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.52
CADD	Benign	6.3
DANN	Benign	0.28

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: rs201092091; hg19: chr18-3116341;