[Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS) with the A3243G mutation of the tRNALeu(UUR) gene of mtDNA in native American haplogroup B2].
BACKGROUND
Mitochondrial encephalopathy, lactic acidosis and cerebrovascular accident syndrome (MELAS) is, from the clinical point of view, one of the best studied mitochondrial multisystemic disorders. This disease has mainly been associated to the mitochondrial desoxyribonucleic acid (mtDNA) mutation A3243G located in the tRNALeu(UUR) gene. Although a relation between European haplogroups and the presence of the 3243 mutation has not been described, nothing is known about the presence of this mutation in native American haplogroups.


METHODS
A 12 year-old female Mexican patient diagnosed with MELAS is reported. Besides neurological, biochemical and cytological examination, we also analyzed the particular mtDNA mutations related to MELAS and the whole genome was sequenced to determine the mitochondrial haplogroup. The A3243G mutation was detected in the patient and maternal relatives (mother and siblings, all of them asymptomatic). The genotype corresponds to the native American haplogroup B2 and contains two private non-synonymous polymorfisms.


CONCLUSIONS
All the members of the family studied present different percentage of the A3243G mutation, being the patient who presented the highest value. The mtDNA genotype corresponds to the native American haplogroup B2 and the private polymorphisms do not confer any phenotypic modification in MELAS syndrome.
Delgado-Sánchez
R
R
Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, México.
Zárate-Moysen
A
A
Monsalvo-Reyes
A
A
Herrero
M D
MD
Ruiz-Pesini
E
E
López-Pérez
M
M
Montoya
J
J
Montiel-Sosa
J F
JF
D002648:Child; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D007198:Indians, North American / Q000235:genetics*; D017241:MELAS Syndrome / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D012356:RNA, Transfer, Leu / Q000235:genetics*
D004272:DNA, Mitochondrial; D012356:RNA, Transfer, Leu