Energy charge is not decreased in lymphocytes of patients with Leber's hereditary optic neuropathy with the 11,778 mutation.
OBJECTIVE
A defect in mitochondrial energy conservation is strongly suggested to be involved in the pathogenesis of Leber's hereditary optic neuropathy (LHON). The authors therefore compared the energy charge in lymphocytes among patients with LHON, their asymptomatic maternal lineages, and normal control subjects.


METHODS
Blood samples were obtained from 7 patients, 10 asymptomatic maternal relatives, and 16 normal subjects. Molecular analysis confirmed that all had the homoplasmic 11,778 point mutation in the mtDNA of their blood cells. The concentrations of adenosine triphosphate (ATP), diphosphate (ADP), and monophosphate (AMP) were determined by high-performance liquid chromatography. The energy charge was calculated as (ATP + 1/2 ADP)/(ATP + ADP + AMP).


RESULTS
The mean energy charges of lymphocytes were 0.871 +/- 0.049 in patients with LHON, 0.884 +/- 0.061 in their asymptomatic maternal relatives, and 0.885 +/- 0.061 in normal controls, respectively. No statistically significant difference was found among the three groups.


CONCLUSIONS
Although the study did not find the anticipated change in energy charge in peripheral blood cells, this neither confirms nor rejects the notion that a defect in the mitochondrial oxidative phosphorylation system is involved in the pathogenesis of LHON.
Yen
M Y
MY
Department of Ophthalmology, Taipei Veterans General Hospital, Taiwan, Republic of China.
Lee
J F
JF
Liu
J H
JH
Wei
Y H
YH
D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D015418:Optic Atrophies, Hereditary / Q000235:genetics / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D017354:Point Mutation
D004272:DNA, Mitochondrial; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate