T16189C mitochondrial DNA variant is associated with metabolic syndrome in Caucasian subjects

Different nuclear genes are thought to be involved in the regulation of the complex phenotype of metabolic syndrome (MS) and their number is increasing. A mutation in mitochondrial DNA (mtDNA), T4291C in transfer RNA isoleucine (tRNAile), has been associated with MS in a large American family. In addition, a mtDNA T16189C variant, already known to be associated with insulin resistance and type 2 diabetes mellitus in Caucasians, seems to underlie susceptibility to MS in the Chinese population. Our aim was to verify the T4291C and T16189C variants in subjects affected by different phenotypes of MS.

Seventy patients with MS and 35 healthy individuals were investigated for the presence of the mtDNA variants by polymerase chain reaction-restriction fragment length polymorphism analysis.

The T4291C variant was absent in patients and in controls. The T16189C variant was more frequent in patients with MS than in control subjects (21.4% versus 5.7%, P<0.04) and was associated with hypertension (P=0.01), waist circumference (P=0.02), body mass index (P=0.009), visceral fat thickness (P=0.04), homeostasis model assessment (P=0.03), and the number of MS diagnostic criteria (P=0.01).

The mtDNA T16189C variant is associated with MS and its different clinical expressions. Prospective studies are warranted to establish the clinical relevance of this association.