Is MTM1 p.Ile136= (c.408C>T) pathogenic?

MTM1 p.Ile136= (c.408C>T) is classified Likely benign in MTM1 (ClinVar, Single submitter, 1 submitter; last evaluated 2023-08-08). Very rare (popmax 0.0028%, nfe); Associated with X-linked myotubular myopathy.

What condition is associated with MTM1 p.Ile136= (c.408C>T)?

MTM1 p.Ile136= (c.408C>T) is associated with X-linked myotubular myopathy (ClinVar).

How common is MTM1 p.Ile136= (c.408C>T) in the general population?

MTM1 p.Ile136= (c.408C>T) is very rare (popmax 0.0028%, nfe) (gnomAD).

How is X-linked centronuclear myopathy inherited?

Typically X-linked recessive (Orphanet). A genetic counselor can assess individual risk for a family.

MTM1 p.Ile136=

c.408C>T · rs781852283 · VCV2739362

Likely benign Single submitter

Classification

Likely benign

ClinVar

Review

Single submitter ★☆☆☆

ClinVar · 1 submitter

gnomAD v4.1

Rare

very rare (popmax 0.0028%, nfe)

Conditions

X-linked myotubular myopathy

Computational evidence

Protein change
Missense predictors do not apply to this variant type; conservation carries the signal.
Splicing
SpliceAI	—	not assessed · no allele here is in the release
Constraint at this position
Conservation	phyloP 2.2	GERP -0.37, phastCons 1
Overall
CADD	10.56	PHRED · no single calibrated threshold — expert panels disagree

Population frequency

gnomAD v4.1 · exomes + genomes

Grpmax group 0.0028% European (non-Finnish) · 25/893,535 alleles

Filtering AF 0.00192% ClinGen BA1/BS1 input FAF95, joint · FAF99 0.00162%

Overall 0.00237% 26/1,096,113 alleles · very rare

Ancestry group	Frequency	1 in
European (non-Finnish)grpmax	0.0028%	35,741
Remaining individualsnot grpmax-eligible	0.0021%	47,583

Rarity supports pathogenicity (ACMG PM2); frequency above a disease-specific BA1/BS1 threshold argues against it. A variant frequent in one ancestry group can be near-absent in others, so a single global figure can mislead.

Variant & gene context

Gene: MTM1
Protein: p.Ile136=
Coding: c.408C>T
MANE Select: NM_000252
dbSNP: rs781852283
Type: single nucleotide variant
Location: chrX:150619103 (GRCh38)
Structure: AlphaFold pLDDT 90.10

Full MTM1 gene report on Sugi Atlas → Gene function, pathways, protein structure, interactions & more

Disease context

X-linked myotubular myopathy — disease report on Sugi Atlas → Associated genes, phenotypes, clinical trials & treatments

For X-linked centronuclear myopathy (Orphanet):

Inheritance: X-linked recessive
Onset: Antenatal, Neonatal
Prevalence: 1-9 / 100 000 (France)

Similar variants

MTM1 c.1644+1G>A Pathogenic ★★★ same condition
MTM1 p.Arg224Ter Pathogenic ★★★ same condition
MTM1 p.Arg69Cys Pathogenic ★★★ same condition
MTM1 p.Gln451= Likely pathogenic ★★★ same condition
MTM1 p.Glu404Lys Pathogenic ★★★ same condition
MTM1 p.Pro205Leu Pathogenic ★★★ same condition
MTM1 p.Trp230Arg Likely pathogenic ★★★ same condition
MTM1 p.Tyr192Cys Likely pathogenic ★★★ same condition

Built on 18 open, versioned datasets — ClinVar, gnomAD, AlphaMissense, REVEL, ClinGen & more — plus Sugi Variant's own cross-source analysis. Source data 2026-01–2026-10, ClinVar 2026-10. Full sources & versions →

Cite Sugi Variant

Gür T. Sugi Variant: A Deterministic Per-Variant Germline Reference from a Knowledge Graph for Humans and AI Agents. 2026. doi:10.5281/zenodo.21509445. This variant: https://sugi.bio/variant/mtm1-p-ile136 (accessed [today's date]).

Preprint & method: sugi.bio/variant/method Machine-readable: this page as Markdown