rs587783850

Variant names:

• chrX-150645683-G-A
• rs587783850
• NM_000252.3:c.679G>A
• MTM1 p.Val227Met

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1 PM2 PP3 PP5_Very_Strong

The NM_000252.3(MTM1):​c.679G>A​(p.Val227Met) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 14/23 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V227L) has been classified as Uncertain significance. The gene MTM1 is included in the ClinGen Criteria Specification Registry.

• Frequency: Genomes: not found (cov: 23)
• Consequence: MTM1 NM_000252.3 missense, splice_region
• Scores: Splicing: ADA: 0.9996
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 9.96
• Publications: 5 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: ClinGen, G2P, Orphanet, Genomics England PanelApp, Myriad Women's Health, Labcorp Genetics (formerly Invitae), Ambry Genetics

ACMG classification

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

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_000252.3
• 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.
• PP5: Variant X-150645683-G-A is Pathogenic according to our data. Variant chrX-150645683-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 158997.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000252.3. 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
	MTM1	NM_000252.3	MANE Select	c.679G>A	p.Val227Met	missense splice_region	Exon 9 of 15	NP_000243.1	Q13496-1
	MTM1	NM_001376908.1		c.679G>A	p.Val227Met	missense splice_region	Exon 9 of 15	NP_001363837.1	Q13496-1
	MTM1	NM_001376906.1		c.679G>A	p.Val227Met	missense splice_region	Exon 9 of 15	NP_001363835.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTM1	ENST00000370396.7	TSL:1 MANE Select	c.679G>A	p.Val227Met	missense splice_region	Exon 9 of 15	ENSP00000359423.3	Q13496-1
	MTM1	ENST00000688403.1		c.-66G>A		5_prime_UTR_premature_start_codon_gain	Exon 4 of 10	ENSP00000508944.1	A0A8I5KQR6
	MTM1	ENST00000690282.1		c.-66G>A		5_prime_UTR_premature_start_codon_gain	Exon 4 of 10	ENSP00000509809.1	A0A8I5KQR6

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 23

Alfa AF: 0.00 Hom.: 0

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	-	-	Severe X-linked myotubular myopathy (3)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.76
BayesDel_addAF	Pathogenic	0.65	D
BayesDel_noAF	Pathogenic	0.70
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.98	D
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.6	H
PhyloP100		10
PrimateAI	Pathogenic	0.84	D
PROVEAN	Uncertain	-2.9	D
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Varity_R		0.95
gMVP		0.94
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.97
SpliceAI score (max)		0.050		Details are displayed if max score is > 0.2

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

dbSNP: rs587783850;

hg19: chrX-149814156;