Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong
The ENST00000498286.6(MTO1):c.983G>T(p.Arg328Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0000105 in 1,613,824 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R328H) has been classified as Uncertain significance.
MTO1 (HGNC:19261): (mitochondrial tRNA translation optimization 1) This gene encodes a mitochondrial protein thought to be involved in mitochondrial tRNA modification. The encoded protein may also play a role in the expression of the non-syndromic and aminoglycoside-induced deafness phenotypes associated with a specific mutation in the mitochondrial 12S rRNA gene. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Mitochondrial hypertrophic cardiomyopathy with lactic acidosis due to MTO1 deficiency Uncertain:1
Uncertain significance, criteria provided, single submitter
clinical testing
Labcorp Genetics (formerly Invitae), Labcorp
Aug 13, 2021
This sequence change replaces arginine with leucine at codon 328 of the MTO1 protein (p.Arg328Leu). The arginine residue is moderately conserved and there is a moderate physicochemical difference between arginine and leucine. This variant is present in population databases (rs142148270, ExAC 0.001%). This variant has not been reported in the literature in individuals affected with MTO1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -