The Novel Mitochondrial Heteroplasmic Mutation (m.9140 C>G) in an Iranian Family with Long QTS LQT3

Mitochondrial DNA (mtDNA) could be considered a candidate modifier factor for Syndrome of Long QT (LQTS), since mitochondrial oxidative stress is thought to be involved in ATP production. It has been reported that the activity of ion channels in cardiomyocytes is sensitive to ATP level. We searched 40% of the entire mitochondrial genome in an Iranian family with LQT3 for mutation by PCR-SSCP and DNA sequencing. We report four new mutations and one reported mutation, leading to an amino acid substitution and two mutations in mitochondrial tRNA. We found statistically significant correlation (r = 0.737) between QTc (ms) and age of LQTS patients. Our data suggest that these mitochondrial mutations in a family with LQTS might be responsible mitochondrial defects and increase the gravity of Syndrome of Long QT LQTS