[Screening of mitochondrial deoxyribonucleic acid 3271T > C, 8356T > C, 9176T > C/G and 13513G > A mutations in mitochondrial encephalomyopathies].

Objective: To investigate the spectrum of mitochondrial DNA (deoxyribonucleic acid) 3271T > C, 8356T > C, 9176T > C/G and 13513G > A mutations in Chinese patients with mitochondrial encephalomyopathies.

Methods: Peripheral blood samples were collected from 500 mitochondrial encephalomyopathies patients clinically diagnosed as mitochondrial encephalomyopathy lactic acidosis & stroke-like episodes (MELAS), myoclonus epilepsy & ragged-red fibers (MERRF) or Leigh's syndrome from October 2005 to October 2009. The methods of PCR- polymerase chain reaction-restriction fragment length polymorphism (RFLP) and PCR-sequencing were performed to identify the mutations.

[Analysis of clinical phenotype in 42 nuclear pedigrees carrying mitochondrial DNA A3243G mutation].

Objective: A3243G mutation in mitochondrial DNA is the most common pathogenic point mutation causing a variety of phenotypes. The clinical phenotype and the relationship between the clinical phenotype and the ratio of A3243G mutation were studied in the members from nuclear families carrying A3243G mutation.

Methods: A total of 42 families carrying A3243G mutation were recruited and their clinical symptoms, laboratory results and the ratio of A3243G analyzed.