Leber's hereditary optic neuropathy: clinical and molecular profile of a Brazilian sample.
OBJECTIVE
The aim of this study was to describe clinical features and search for primary mitochondrial DNA (mtDNA) mutations in 13 unrelated Brazilian patients with Leber's hereditary optic neuropathy (LHON).


METHODS
Analysis of the G11778A, G3460A, and T14484C mutations was done by polymerase chain reaction and restriction fragment length polymorphism, and mutations were confirmed by direct sequencing. Mean age of onset was 24.5 years and all cases were bilateral.


RESULTS
Sex ratio (12M:1F) and frequency of simultaneous involvement (9/13) were higher than in other studies. In nine cases there was familial recurrence: 24 male and two female relatives. Ten patients had a mutation: G11778A in six, T14484C in three and one G3460A. The frequency of patients bearing a primary mutation was lower than that described in multicentric studies but similar to that observed among Asians. A higher frequency of the T14484C mutation was detected.


CONCLUSIONS
The contribution of Amerindians and Africans to the Brazilian mtDNA pool may account for differences in the type and frequency of primary LHON mutations.
Maciel-Guerra
Andréa Trevas
AT
Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, São Paulo, Brasil. atmg@fcm.unicamp.br
Zanchetta
Luciene Maria
LM
Amaral Fernandes
Marcela Scabello
MS
Andrade
Paula Baloni
PB
do Amor Divino Miranda
Paulo Maurício
PM
Sartorato
Edi Lúcia
EL
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001938:Brazil / Q000453:epidemiology; D004272:DNA, Mitochondrial / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D029242:Optic Atrophy, Hereditary, Leber / Q000453:epidemiology / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012744:Sex Ratio; D055815:Young Adult
D004272:DNA, Mitochondrial