The role of mitochondrial haplogroups in non-arteritic anterior ischemic optic neuropathy. 
To investigate a possible association between mitochondrial haplogroups and non-arteritic anterior ischemic optic neuropathy (NAION).  We compared the prevalence of various mitochondrial haplogroups in 24 NAION patients and 552 maternally unrelated ethnic controls.  All patients and controls were Saudi Arabs.  NAION patients had substantially more potentially pathologic mtDNA nucleotide changes (10/24) than Controls (0/159) and a significantly elevated mean relative mtDNA content (2.62 +/- 1.21) than controls (1.33 +/- 0.34; p < or = 0.001).  There was no statistically significant difference between patients and controls for any of the mitochondrial haplogroups tested.  Mitochondrial haplogroups do not appear to contribute to the pathogenesis of NAION in this cohort; however, mitochondrial abnormalities still seem likely to play a role.