5-137870667-C-T

Position:

• chr5-137870667-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 5P and 4B. PM1 PM5 PP3 BS2

The NM_006790.3(MYOT):​c.16C>T​(p.Arg6Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000124 in 1,613,894 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R6H) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: MYOT NM_006790.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.43

Genes affected

MYOT (HGNC:12399): (myotilin) This gene encodes a cystoskeletal protein which plays a significant role in the stability of thin filaments during muscle contraction. This protein binds F-actin, crosslinks actin filaments, and prevents latrunculin A-induced filament disassembly. Mutations in this gene have been associated with limb-girdle muscular dystrophy and myofibrillar myopathies. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.[provided by RefSeq, Oct 2008]

PKD2L2-DT (HGNC:55557): (PKD2L2 divergent transcript)

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM1: In a region_of_interest Disordered (size 45) in uniprot entity MYOTI_HUMAN there are 6 pathogenic changes around while only 1 benign (86%) in NM_006790.3
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr5-137870668-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 30407.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=2}.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.775
• BS2: High AC in GnomAdExome4 at 19 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYOT	NM_006790.3	c.16C>T	p.Arg6Cys	missense_variant	2/10	ENST00000239926.9
PKD2L2-DT	XR_948815.3	n.303-11404G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYOT	ENST00000239926.9	c.16C>T	p.Arg6Cys	missense_variant	2/10	1	NM_006790.3	P1
PKD2L2-DT	ENST00000514616.6	n.320-11404G>A		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152160 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.0000130 AC: 19 AN: 1461734 Hom.: 0 Cov.: 31 AF XY: 0.00000963 AC XY: 7 AN XY: 727178

Gnomad4 AFR exome AF: 0.0000299

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: 0.0000153

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152160 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74334

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Myofibrillar myopathy 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 13, 2023

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 6 of the MYOT protein (p.Arg6Cys). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MYOT-related conditions. ClinVar contains an entry for this variant (Variation ID: 2059499). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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	Uncertain	0.45
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
CADD	Pathogenic	31
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.76
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Uncertain	0.93	D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.78	D
MetaSVM	Uncertain	0.56	D
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-5.2	D
REVEL	Pathogenic	0.78
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.75
MutPred		0.37		Loss of MoRF binding (P = 0.0978);
MVP		0.95
MPC		0.81
ClinPred		1.0	D
GERP RS		5.5
gMVP		0.84

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: rs1264310581; hg19: chr5-137206356;