17-10392646-C-G

Variant names:

• chr17-10392646-C-G
• rs143876651
• NM_002472.3:c.5464G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_002472.3(MYH8):​c.5464G>C​(p.Val1822Leu) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.00000137 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V1822I) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYH8 NM_002472.3 missense, splice_region
• Scores: Splicing: ADA: 0.9998
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.96
• Publications: 1 publications found

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]

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]

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 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. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002472.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH8	NM_002472.3	MANE Select	c.5464G>C	p.Val1822Leu	missense splice_region	Exon 38 of 40	NP_002463.2	P13535
	MYHAS	NR_125367.1		n.76+9439C>G		intron	N/A

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH8	ENST00000403437.2	TSL:5 MANE Select	c.5464G>C	p.Val1822Leu	missense splice_region	Exon 38 of 40	ENSP00000384330.2	P13535
	MYHAS	ENST00000399342.6	TSL:3	n.76+9439C>G		intron	N/A
	MYHAS	ENST00000581304.2	TSL:3	n.52+9439C>G		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251482 AF XY: 0.00

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461872 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727238

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111992

Other (OTH) AF: 0.00 AC: 0 AN: 60394

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.39
BayesDel_addAF	Pathogenic	0.16	D
BayesDel_noAF	Uncertain	0.0
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Benign	0.27	T
Eigen	Benign	0.13
Eigen_PC	Uncertain	0.23
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.012	T
MetaRNN	Uncertain	0.74	D
MetaSVM	Uncertain	0.077	D
MutationAssessor	Uncertain	2.5	M
PhyloP100		4.0
PrimateAI	Uncertain	0.70	T
PROVEAN	Benign	-1.8	N
REVEL	Uncertain	0.61
Sift	Benign	0.044	D
Sift4G	Benign	0.17	T
Polyphen		0.012	B
Vest4		0.77
MutPred		0.68		Loss of MoRF binding (P = 0.0968)
MVP		0.79
MPC		0.44
ClinPred		0.93	D
GERP RS		4.9
Varity_R		0.19
gMVP		0.71
Mutation Taster		=75/25	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.020		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs143876651; hg19: chr17-10295963;