17-10399648-G-C

Variant names:

• chr17-10399648-G-C
• rs34953692
• NM_002472.3:c.3757C>G

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.3757C>G​(p.Arg1253Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,818 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 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. R1253C) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYH8 NM_002472.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 1.91
• Publications: 0 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: MetaRNN computational evidence supports a deleterious effect, 0.841

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH8	NM_002472.3	MANE Select	c.3757C>G	p.Arg1253Gly	missense	Exon 28 of 40	NP_002463.2
	MYHAS	NR_125367.1		n.77-6500G>C		intron	N/A

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH8	ENST00000403437.2	TSL:5 MANE Select	c.3757C>G	p.Arg1253Gly	missense	Exon 28 of 40	ENSP00000384330.2
	MYHAS	ENST00000399342.6	TSL:3	n.77-6500G>C		intron	N/A
	MYHAS	ENST00000581304.2	TSL:3	n.53-6500G>C		intron	N/A

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461818 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727200

⚠️ 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: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44722

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86256

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5738

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111986

Other (OTH) AF: 0.00 AC: 0 AN: 60392

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), 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	Benign	0.32
BayesDel_addAF	Uncertain	0.074	D
BayesDel_noAF	Benign	-0.13
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.54	D
Eigen	Uncertain	0.55
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.91	D
M_CAP	Benign	0.027	D
MetaRNN	Pathogenic	0.84	D
MetaSVM	Uncertain	0.30	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		1.9
PrimateAI	Benign	0.41	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.65
Sift	Pathogenic	0.0	D
Sift4G	Benign	0.075	T
Polyphen		0.96	D
Vest4		0.77
MutPred		0.62		Loss of MoRF binding (P = 0.0128)
MVP		0.82
MPC		0.66
ClinPred		0.99	D
GERP RS		4.4
Varity_R		0.51
gMVP		0.49

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

Other links and lift over

dbSNP: rs34953692; hg19: chr17-10302965;