chrX-150649757-CG-CG

Variant names:

• chrX-150649757-C-C
• NM_000252.3:c.

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_Strong PM2

The ENST00000370396.7(MTM1):​c. variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. The gene MTM1 is included in the ClinGen Criteria Specification Registry.

• Frequency: Genomes: not found (cov: 23)
• Consequence: MTM1 ENST00000370396.7 splice_donor, intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.52
• Publications: 0 publications found

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]

MTM1 Gene-Disease associations (from GenCC):

• X-linked myotubular myopathy

  Inheritance: XL Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, G2P, Myriad Women’s Health, Ambry Genetics

ACMG classification

Specifications for MTM1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Likely_pathogenic. The variant received 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.102649 fraction of the gene. No cryptic splice site detected. Exon removal is inframe change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000370396.7. 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
	MTM1	NM_000252.3	MANE Select	c.		intron	N/A	NP_000243.1	Q13496-1
	MTM1	NM_001376908.1		c.		intron	N/A	NP_001363837.1	Q13496-1
	MTM1	NM_001376906.1		c.		intron	N/A	NP_001363835.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTM1	ENST00000370396.7	TSL:1 MANE Select	c.		splice_donor intron	N/A	ENSP00000359423.3	Q13496-1
	MTM1	ENST00000689314.1		c.		splice_donor intron	N/A	ENSP00000510607.1	A0A8I5KZ76
	MTM1	ENST00000866458.1		c.		splice_donor intron	N/A	ENSP00000536517.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 23

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		2.5

Splicing

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

hg19: chrX-149818230;