ABSTRACT
Friedreich ataxia [FRDA] is an inherited recessive disorder. Mitochondrial DNA is a candidate modifying factor for FRDA.The purpose of this study was to investigate the relationship between the tRNA[Leu [CUN]] 12308 A> G mutation and age of onset in Friedreich ataxia. The 12308 A> G substitution in mitochondrial tRNA[Leu [CUN]] was examined in DNA samples from 30 Friedreich ataxia patients and 48 control subjects by temporal temperature gradient gel electrophoresis [TTGE] and sequencing. Logistic regression was used to determine of cutoff age of onset. Twenty-two patients had the 12308 A> G mutation, and we found that its overall prevalence was significantly higher in 20 patients aged 17 years or younger than in 2 patients aged over 17 years [90% versus 10%]. The 12308 A> G mutation lies in a region that has been highly conserved between species. Our results show that the 12308 A > G mutation is associated with earlier age of onset in Friedreich ataxia. Thus, this mutation might cause the younger age of onset in FRDA