17-10521351-C-T

Position:

• chr17-10521351-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_017534.6(MYH2):​c.5755G>A​(p.Ala1919Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH2 NM_017534.6 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.91

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]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MYH2. . Gene score misZ 1.9724 (greater than the threshold 3.09). Trascript score misZ 4.733 (greater than threshold 3.09). GenCC has associacion of gene with childhood-onset autosomal recessive myopathy with external ophthalmoplegia, hereditary inclusion body myopathy-joint contractures-ophthalmoplegia syndrome, myopathy, proximal, and ophthalmoplegia.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.866

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH2	NM_017534.6	c.5755G>A	p.Ala1919Thr	missense_variant	40/40	ENST00000245503.10
MYHAS	NR_125367.1	n.168-46186C>T		intron_variant, non_coding_transcript_variant
MYH2	NM_001100112.2	c.5755G>A	p.Ala1919Thr	missense_variant	40/40

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH2	ENST00000245503.10	c.5755G>A	p.Ala1919Thr	missense_variant	40/40	1	NM_017534.6	P1
	ENST00000399342.6	n.207-11973C>T		intron_variant, non_coding_transcript_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251458 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135896

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: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Myopathy, proximal, and ophthalmoplegia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 02, 2020

This sequence change replaces alanine with threonine at codon 1919 of the MYH2 protein (p.Ala1919Thr). The alanine residue is highly conserved and there is a small physicochemical difference between alanine and threonine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with MYH2-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.60
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.56	.;D;D;.
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.99
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;.;D;D
M_CAP	Uncertain	0.28	D
MetaRNN	Pathogenic	0.87	D;D;D;D
MetaSVM	Pathogenic	0.87	D
MutationAssessor	Pathogenic	4.4	.;H;H;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.76	T
PROVEAN	Benign	-0.54	N;D;D;.
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D;D;D;.
Sift4G	Benign	0.32	T;D;D;T
Polyphen		1.0	.;D;D;.
Vest4		0.76
MutPred		0.73		.;Gain of phosphorylation at A1919 (P = 0.099);Gain of phosphorylation at A1919 (P = 0.099);.;
MVP		0.95
MPC		1.1
ClinPred		0.99	D
GERP RS		5.5
Varity_R		0.47
gMVP		0.23

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: rs1464949119; hg19: chr17-10424668;