Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PP3
The NM_016156.6(MTMR2):c.1770G>A(p.Gln590Gln) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.0000136 in 1,612,136 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. 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]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change affects codon 590 of the MTMR2 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MTMR2 protein. This variant also falls at the last nucleotide of exon 14, which is part of the consensus splice site for this exon. This variant is present in population databases (rs778532655, gnomAD 0.004%). 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: 543316). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. 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. -