ClinVar

Description

Note this variant was found in clinical genetic testing performed by one or more labs who may also submit to ClinVar. Thus any internal case data may overlap with the internal case data of other labs. The interpretation reviewed below is that of the Stanford Center for Inherited Cardiovascular Disease. MT-TK m.8342G>A We classify it as a variant of uncertain significance. This variant has not been reported in association with cardiomyopathy in previous publications. It has been reported in association with an unspecified neuromuscular disorder. Tiranti et al (1999) describe an individual with muscle weakness, ophthalmoparesi s and this variant present with 80% heteroplasmy in muscle mtDNA and no heteroplasmy in lymphocyte DNA. The location of the nucleotide change is expected to alter the secondary structure of the resulting tRNA. A number of additional variants in this region of the MT-TK gene have been reported in association with mitochondrial disorders. This variant has not been reported in 6391 individuals at GeneDx, 2704 individuals in mtDB (www.genpath.uu.se/mtDB), 3735 individuals in MitoWheel (http://mitowheel.org/mitowheel.html). Triantis et al (1999) reported that m.8342G>A was not present in 100 presumably healthy controls. Thus in total this variant has not been detected in over 10,000 individuals.