Exp Mol Med.  2008 Jun;40(3):354-360. 10.3858/emm.2008.40.3.354.

A MELAS syndrome family harboring two mutations in mitochondrial genome

• Choi BO
• Hwang JH
• Kim J
• Cho EM
• Cho SY
• Hwang SJ
• Lee HW
• Kim SJ
• Chung KW

• KMID: 756338
• DOI: http://doi.org/10.3858/emm.2008.40.3.354

Abstract

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a genetically heterogeneous mitochondrial disorder with variable clinical symptoms. Here, from the sequencing of the entire mitochondrial genome, we report a Korean MELAS family harboring two homoplasmic missense mutations, which were reported 9957T>C (Phe251Leu) transition mutation in the cytochrome c oxidase subunit 3 (COX3) gene and a novel 13849A>C (Asn505His) transversion mutation in the NADH dehydrogenase subunit 5 (ND5) gene. Neither of these mutations was found in 205 normal controls. Both mutations were identified from the proband and his mother, but not his father. The patients showed cataract symptom in addition to MELAS phenotype. We believe that the 9957T>C mutation is pathogenic, however, the 13849A>C mutation is of unclear significance. It is likely that the 13849A>C mutation might function as the secondary mutation which increase the expressivity of overlapping phenotypes of MELAS and cataract. This study also demonstrates the importance of full sequencing of mtDNA for the molecular genetic understanding of mitochondrial disorders.

Keyword

Asian continental ancestry group; cataract; cytochrome-c oxidase deficiency; DNA, mitochondrial; Korea; MELAS syndrome; mutation, missense; ND5 protein, human

MeSH Terms

Adult
Asian Continental Ancestry Group
DNA Mutational Analysis
DNA, Mitochondrial/analysis/*genetics
Electron Transport Complex I/*genetics
Electron Transport Complex IV/*genetics
Female
Humans
Korea
MELAS Syndrome/*genetics
Male
Middle Aged
Mitochondrial Proteins/*genetics
*Mutation, Missense
Pedigree
Polymorphism, Genetic