rs121434590

Variant names:

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2PP3_StrongPP5_Very_Strong

The NM_002472.3(MYH8):c.2021G>A(p.Arg674Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,613,870 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MYH8
NM_002472.3 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 7.78

Variant links:

Genes affected

MYH8 (HGNC:7578): (myosin heavy chain 8) 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 predominantly expressed in fetal skeletal muscle. This gene is found in a cluster of myosin heavy chain genes on chromosome 17. A mutation in this gene results in trismus-pseudocamptodactyly syndrome. [provided by RefSeq, Sep 2009]

MYH8 links:

ENSG00000272736 (HGNC:):

ENSG00000272736 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 Pathogenic. Variant got 14 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.987

PP5

Variant 17-10406924-C-T is Pathogenic according to our data. Variant chr17-10406924-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 14136.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr17-10406924-C-T is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH8	NM_002472.3 link	c.2021G>A	p.Arg674Gln	missense_variant	Exon 18 of 40	ENST00000403437.2	NP_002463.2	P13535
MYHAS	NR_125367.1 link	n.167+686C>T		intron_variant	Intron 2 of 10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	UniProt
MYH8	ENST00000403437.2 link	c.2021G>A	p.Arg674Gln	missense_variant	Exon 18 of 40	5	NM_002472.3	ENSP00000384330.2	P13535
ENSG00000272736	ENST00000399342.6 link	n.206+647C>T		intron_variant	Intron 2 of 3	3
ENSG00000272736	ENST00000581304.1 link	n.143+686C>T		intron_variant	Intron 2 of 3	3
MYHAS	ENST00000587182.2 link	n.155+686C>T		intron_variant	Intron 2 of 10	5

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152076

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461794

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727196

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:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152076

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74280

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:4

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jul 01, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Mar 14, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Feb 16, 2025	Segregates with disease in many affected individuals from several families in published literature (PMID: 15282353, 17041932); Reported previously as a maternally inherited pathogenic variant in a patient with trismus-pseudocamptodactyly syndrome who also harbored a de novo pathogenic variant in a different gene consistent with a second disorder. It was thought that the combination of these two variants contributed to the more involved phenotype observed in this patient (PMID: 34321323); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 17041932, 15282353, 18049072, 28377322, 20949528, 33109698, 31630644, 34321323, 35982159) -
Pathogenic, criteria provided, single submitter	clinical testing	Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	May 31, 2016	- -

Hecht syndrome

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Feb 02, 2022	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0105 - The mechanism of disease for this gene is not clearly established. (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from arginine to glutamine. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v3) <0.001 for a dominant condition (2 heterozygotes, 0 homozygotes). (SP) 0309 - An alternative amino acid change at the same position has been observed in gnomAD (v2) (5 heterozygotes, 0 homozygotes). (I) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated actin-binding region of the myosin motor domain (UniProt). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. The variant has previously been reported as pathogenic in more than ten unrelated individuals with trismus-pseudocamptodactyly syndrome (MIM#158300) (ClinVar, HGMD, LOVD, PMIDs: 15282353, 17041932, 18049072, 20949528). (SP) 0901 - This variant has strong evidence for segregation with disease. The variant has previously been shown to segregate in affected individuals in several multigenerational families (PMIDs: 15282353, 17041932). (SP) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Pathogenic, no assertion criteria provided	literature only	OMIM	Nov 01, 2010	- -

Carney complex - trismus - pseudocamptodactyly syndrome

Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 01, 2010

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.99

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.44

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.88

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.95

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

M_CAP

Benign

0.072

MetaRNN

Pathogenic

0.99

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

4.3

PrimateAI

Pathogenic

0.84

PROVEAN

Uncertain

-3.4

REVEL

Pathogenic

0.91

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.95

MutPred

0.97

Loss of MoRF binding (P = 0.0797);

MVP

0.96

MPC

0.72

ClinPred

1.0

GERP RS

5.1

Varity_R

0.84

gMVP

0.59

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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

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