Mitochondrial DNA Point Mutations Studies In Hereditary Ataxia

Objective: To study the possible relationship between mitochondrial DNA (mtDNA) and hereditary ataxia (HA). Methods: Polymerase chain reaction (PCR) was used to amplify 4 mtDNA segments of 30 patients with HA,some of their relatives and 35 volunteers. The point 3243,8993,8344 and point 11778 lied in the above 4 mtDNA segments respectively. For the PCR products of point 3243 and 8993, restriction fragment length polymophism (RFLP) was performed to search A3243G,T8993G or T8993C point mutations. For PCR products of point 8344 and 11778, single strand conformation polymorphism (SSCP) was executed to detect mutations. The HA patients'results of SSCP were compared with their relatives'and volunteers'. Sequencing would be carry out to find out exactly mutations in those subjects whose SSCP results were abnormal. Results: We had not found the A3243G,T8993G or T8993C point mutations in our study. All subjects'mtDNA segments of point 8344 had not been found mutations. However,a new mtDNA point mutation--A11893G--was identified in 2 patients and 1 relative without symptoms in pedigree 1. Conclusion: This new point mutation of mtDNA may be related to HA.