Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1PM2PP5_Moderate
The NM_016156.6(MTMR2):c.832C>T(p.Gln278*) variant causes a stop gained 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. Variant has been reported in ClinVar as Pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. Q278Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
MTMR2 (HGNC:7450): (myotubularin related protein 2) This gene is a member of the myotubularin family of phosphoinositide lipid phosphatases. The encoded protein possesses phosphatase activity towards phosphatidylinositol-3-phosphate and phosphatidylinositol-3,5-bisphosphate. Mutations in this gene are a cause of Charcot-Marie-Tooth disease type 4B, an autosomal recessive demyelinating neuropathy. Alternatively spliced transcript variants encoding multiple isoforms have been found for this gene. [provided by RefSeq, Aug 2011]
MTMR2 Gene-Disease associations (from GenCC):
demyelinating hereditary motor and sensory neuropathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
Our verdict: Pathogenic. The variant received 12 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 11-95849835-G-A is Pathogenic according to our data. Variant chr11-95849835-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 241077.Status of the report is criteria_provided_single_submitter, 1 stars.
This sequence change creates a premature translational stop signal at codon 278 (p.Gln278*) of the MTMR2 gene. It is expected to result in an absent or disrupted protein product. For these reasons, this variant has been classified as Pathogenic. While this particular variant has not been reported in the literature, truncating variants in MTMR2 are known to be pathogenic (PMID: 10802647). -