X-150592641-T-G

Position:

• chrX-150592641-T-G

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000252.3(MTM1):​c.27T>G​(p.Tyr9Ter) variant causes a stop gained change involving the alteration of a non-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 Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Y9Y) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 23)
• Consequence: MTM1 NM_000252.3 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.719

Genes affected

MTM1 (HGNC:7448): (myotubularin 1) This gene encodes a dual-specificity phosphatase that acts on both phosphotyrosine and phosphoserine. It is required for muscle cell differentiation and mutations in this gene have been identified as being responsible for X-linked myotubular myopathy. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 175 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-150592641-T-G is Pathogenic according to our data. Variant chrX-150592641-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 2753250.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chrX-150592641-T-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MTM1	NM_000252.3	c.27T>G	p.Tyr9Ter	stop_gained	2/15	ENST00000370396.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MTM1	ENST00000370396.7	c.27T>G	p.Tyr9Ter	stop_gained	2/15	1	NM_000252.3	P1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Severe X-linked myotubular myopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Aug 17, 2023

For these reasons, this variant has been classified as Pathogenic. This variant has not been reported in the literature in individuals affected with MTM1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Tyr9*) in the MTM1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MTM1 are known to be pathogenic (PMID: 9305655, 10063835). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.74	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	33
DANN	Uncertain	1.0
FATHMM_MKL	Benign	0.75	D
MutationTaster	Benign	1.0	A;A;D;D
Vest4		0.90
GERP RS		3.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-149761103; COSMIC: COSV60333621;