GTPBP3 encodes for a modifier of a uridine located in the wobble position of several mt-tRNA species. This base pair modification possibly has a role in the stabilization of tRNA-mRNA interactions.
Recently, Kopajtich et al (Am J Hum Genet. 2014 Dec 4;95(6):708-20. doi: 10.1016/j.ajhg.2014.10.017) described 11 patients in 9 families with compound heterozygous or homozygous mutations in GTPBP3. These patients had an array of features consistent with other disorders of mitochondrial dysfunction including: lactic acidosis, cardiomyopathy, decompensation with intercurrent illness, and encephalopathy. Through mechanistic studies on patient derived cell lines, thus group was able to show abnormalities in oxygen consumption rate and in mitochondrial protein synthesis, thus connecting the variants to mitochondrial functional defects.