chr17-10542874-C-G

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_017534.6(MYH2):c.904+1G>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000393 in 1,424,064 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic 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: 33)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

MYH2
NM_017534.6 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.91

Variant links:

Genes affected

MYH2 (HGNC:7572): (myosin heavy chain 2) Myosins are actin-based motor proteins that function in the generation of mechanical force in eukaryotic cells. Muscle myosins are heterohexamers composed of 2 myosin heavy chains and 2 pairs of nonidentical myosin light chains. This gene encodes a member of the class II or conventional myosin heavy chains, and functions in skeletal muscle contraction. This gene is found in a cluster of myosin heavy chain genes on chromosome 17. A mutation in this gene results in inclusion body myopathy-3. Multiple alternatively spliced variants, encoding the same protein, have been identified. [provided by RefSeq, Sep 2009]

MYH2 links:

MYHAS (HGNC:50609): (myosin heavy chain gene cluster antisense RNA) Predicted to enable primary miRNA binding activity. Predicted to be involved in response to muscle activity and skeletal muscle fiber development. Predicted to act upstream of or within with a positive effect on gene expression. Predicted to be located in cytoplasm and nucleus. [provided by Alliance of Genome Resources, Apr 2022]

MYHAS links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.01699279 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
MYH2	NM_017534.6 link	c.904+1G>C	splice_donor_variant, intron_variant	Intron 10 of 39	ENST00000245503.10	NP_060004.3	Q9UKX2-1
MYH2	NM_001100112.2 link	c.904+1G>C	splice_donor_variant, intron_variant	Intron 10 of 39		NP_001093582.1	Q9UKX2-1
MYHAS	NR_125367.1 link	n.168-24663C>G	intron_variant	Intron 2 of 10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH2	ENST00000245503.10 link	c.904+1G>C		splice_donor_variant, intron_variant	Intron 10 of 39	1	NM_017534.6	ENSP00000245503.5		Q9UKX2-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000401

AC:

AN:

249492

Hom.:

AF XY:

0.00000741

AC XY:

AN XY:

134936

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000888

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000393

AC:

AN:

1424064

Hom.:

Cov.:

AF XY:

0.0000380

AC XY:

AN XY:

710980

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000519

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Myopathy, proximal, and ophthalmoplegia

Uncertain:1

Uncertain significance, criteria provided, single submitter

curation

Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard

May 02, 2023

The heterozygous c.904+1G>C variant in MYH2 was identified by our study, in the compound heterozygous state with a likely pathogenic variant (dbSNP ID: rs1234832404), in one individual with myopathy, limb-girdle muscle weakness, and ophthalmoplegia. This individual also carried a likely pathogenic variant (dbSNP ID: rs1234832404), however the phase of these variants are unknown at this time. The c.904+1G>C variant in MYH2 has not been previously reported in individuals with autosomal recessive proximal myopathy and ophthalmoplegia, but has been identified in 0.0009% (1/112616) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs879255253). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. A different nucleotide change that also results in a splice donor variant at the same site, c.904+1G>A (ClinVar Variation ID: 183661) has been previously reported pathogenic, and the variant being assessed here, c.904+1G>C, is predicted by SpliceAI to have a similar effect on splicing. This variant is located in the 5' splice region. Computational tools predict a splicing impact, though this information is not predictive enough to determine pathogenicity. There is an in-frame cryptic splice site 99 bases from the intron-exon boundary, providing evidence that this variant may delete 33 amino acids instead of causing loss of function. However, this information is not predictive enough to determine pathogenicity. Loss of function of the MYH2 gene is an established disease mechanism in autosomal recessive proximal myopathy and ophthalmoplegia. In summary, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PVS1_Moderate, PS1_Supporting, PM2_Supporting, PM3_Supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.40

CADD

Pathogenic

DANN

Uncertain

0.99

Eigen

Pathogenic

1.2

Eigen_PC

Pathogenic

1.0

FATHMM_MKL

Pathogenic

1.0

GERP RS

4.9

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_DL_spliceai

1.0

Position offset: 1

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over