Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PVS1_StrongPM2
The NM_016156.6(MTMR2):c.1843C>T(p.Gln615*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000411 in 1,460,964 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).
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: Likely_pathogenic. The variant received 6 ACMG points.
PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
This sequence change creates a premature translational stop signal (p.Gln615*) in the MTMR2 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 29 amino acid(s) of the MTMR2 protein. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MTMR2-related conditions. ClinVar contains an entry for this variant (Variation ID: 864368). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -