Related Experiment Video
Updated: May 15, 2026

Genotyping Single Nucleotide Polymorphisms in the Mitochondrial Genome by Pyrosequencing
Published on: February 10, 2023
[Clinical heterogeneity associated with mitochondrial DNA A8344G point mutation]
Juan Zhao1, Dan-hua Zhao, Wei Zhang
1Department of Neurology, Peking University First Hospital, Beijing 100034, China.
Objective:
To report the clinical features of mitochondrial disease caused by mitochondrial DNA (mtDNA) A8344G point mutation.
Methods:
We analyzed the clinical presentations and muscular pathological changes in 10 patients with genetically confirmed mtDNA A8344G point mutation.
Results:
Among them, 6 patients presented as juvenile-onset myoclonic epilepsy with ragged red fibers (MERRF) syndrome, 2 suffered infant-onset Leigh syndrome and the remaining 2 were diagnosed as limb-girdle mitochondrial myopathy. The mtDNA A8344G mutation load from muscle samples showed that patients with Leigh syndrome>MERRF syndrome>mitochondrial myopathy (87.2%, 88.4%>69.0%-86.8%>67.2%, 58.4%).
Conclusions:
Mitochondrial disease caused by A8344G point mutation shows a great heterogeneity. The mutation load of muscle mtDNA might be associated with the severity of clinical phenotype, the higher mutation load, the more severe clinical presentations.
Related Concept Videos
Animal Mitochondrial Genetics
Point and Frameshift Mutations
Mitochondrial Precursor Proteins
Most of the mitochondrial precursors...
Mitochondrial Membranes
Mitochondrial Membranes
Mitochondrial Protein Sorting
Most of these mitochondrial proteins are encoded by the nucleus and imported to the mitochondria as unfolded or loosely folded precursors. Mitochondrial precursors...

