[A case of Leber optic neuropathy with a new point mutation in the cytochrome b gene].
BACKGROUND
Leber's hereditary optic neuropathy (LHON) is associated with mutations in the mitochondrial DNA (mtDNA). We report the clinical and molecular genetic findings of a patient who does not carry any of the common LHON mutations.


METHODS
Clinical data were collected for the affected patient and two unaffected maternal family members. Complete sequence analysis of the mtDNA protein coding region was performed in the affected patient.


RESULTS
Clinical examination of the affected patient showed typical features of LHON. A nucleotide exchange was detected at np14894 replacing an evolutionarily conserved phenylalanine by a leucine in the cytochrome b gene. The mutation was also present in two unaffected maternal family members, but absent in 60 other LHON lineages and 175 unrelated controls.


CONCLUSIONS
Cytochrome b plays an important role in the electron transport chain of mitochondrial oxidative phosphorylation, and some mutations in the gene encoding cytochrome b have been associated with LHON. Our results may imply that the novel mutation at np14894 is responsible for LHON in this family.