rs772009177

Variant names:

• chr18-3193813-C-G
• rs772009177
• NM_003803.4:c.431+5G>C

Your query was ambiguous. Multiple possible variants found:

• chr18-3193813-C-G
• chr18-3193813-C-T

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_003803.4(MYOM1):​c.431+5G>C variant causes a splice region, intron change. The variant allele was found at a frequency of 0.00000274 in 1,458,352 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: MYOM1 NM_003803.4 splice_region, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.36
• Publications: 1 publications found

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 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000265399 (HGNC:):

ACMG classification

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYOM1	NM_003803.4	c.431+5G>C		splice_region_variant, intron_variant	Intron 3 of 37	ENST00000356443.9	NP_003794.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYOM1	ENST00000356443.9	c.431+5G>C		splice_region_variant, intron_variant	Intron 3 of 37	1	NM_003803.4	ENSP00000348821.4
MYOM1	ENST00000261606.11	c.431+5G>C		splice_region_variant, intron_variant	Intron 3 of 36	1		ENSP00000261606.7
ENSG00000265399	ENST00000580139.1	n.121-63C>G		intron_variant	Intron 1 of 4	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.0000243 AC: 6 AN: 246554 AF XY: 0.0000374

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000178

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1458352 Hom.: 0 Cov.: 30 AF XY: 0.00000552 AC XY: 4 AN XY: 725278

African (AFR) AF: 0.00 AC: 0 AN: 33300

American (AMR) AF: 0.0000909 AC: 4 AN: 44020

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25976

East Asian (EAS) AF: 0.00 AC: 0 AN: 39632

South Asian (SAS) AF: 0.00 AC: 0 AN: 85580

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53294

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5744

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110568

Other (OTH) AF: 0.00 AC: 0 AN: 60238

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Aug 04, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 3 of the MYOM1 gene. It does not directly change the encoded amino acid sequence of the MYOM1 protein. It affects a nucleotide within the consensus splice site. This variant is present in population databases (rs772009177, gnomAD 0.02%). 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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 410256). This variant has not been reported in the literature in individuals affected with MYOM1-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.31
CADD	Uncertain	24
DANN	Benign	0.91
PhyloP100		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.97
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.40		Position offset: 25
DS_DL_spliceai		0.96		Position offset: 5

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs772009177; hg19: chr18-3193811;