Molecular-clinical correlation in a family with a novel heteroplasmic Leigh syndrome missense mutation in the mitochondrial cytochrome c oxidase III gene.
Cytochrome c oxidase is an essential component of the mitochondrial respiratory chain that catalyzes the reduction of molecular oxygen by reduced cytochrome c. In this study, the authors report the second mutation associated with Leigh syndrome in the blood and buccal mucosa of 2 affected members of a Tunisian family. It was a novel heteroplasmic missense mitochondrial mutation at nucleotide 9478 in the gene specifying subunit III of cytochrome c oxidase substituting the valine at position 91 to alanine in a highly conserved amino acid. It was found with a high mutant load in tissues derived from endoderm (buccal mucosa) and mesoderm (blood). However, it was nearly absent in tissue derived from ectoderm (hair follicles). It was absent in 120 healthy controls, and PolyPhen analysis showed that the hydropathy index changed from +1.276 to +0.242, and the number of structures of the 3D protein decreased from 39 to 32.
Mkaouar-Rebai
Emna
E
Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine de Sfax, Tunisia. emna_mkaouar@mai12world.com
Ellouze
Emna
E
Chamkha
Imen
I
Kammoun
Fatma
F
Triki
Chahnez
C
Fakhfakh
Faiza
F
D004252:DNA Mutational Analysis; D003576:Electron Transport Complex IV / Q000235:genetics*; D005260:Female; D006801:Humans; D007888:Leigh Disease / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D011859:Radiography
D003576:Electron Transport Complex IV