Objective: To study the possible relationship between the mitochondrial DNA (mtDNA) mutation and spinocerebellar ataxia type 3 (SCA3).
Methods: Genetic diagnosis of SCA3 was made by detecting the CAG-repeat expansion of MJD1 gene using PCR and DNA sequencing techniques. Then polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) was performed to analyze the mitochondrial DNA extracted from peripheral white blood cells from 43 patients and presymptomatic individuals diagnosed according to CAG expansion, and 30 healthy individuals. Mitochondrial DNAs of subjects with abnormal SSCP were sequenced.
Results: A new mitochondrial DNA deletion of 9 bp at mtDNA 8282-8290 was identified in 1 patient and 3 presymptomatic individuals.
Conclusion: A new deletion mutation of mitochondrial DNA in 1 SCA3 patient and 3 presymptomatic individuals is reported.