Mae III positively detects the mitochondrial mutation associated with type I Leber's hereditary optic neuropathy.

Leber's hereditary optic neuropathy is a blinding disease that usually causes acute or subacute central visual loss in adolescent and young adult males. In patients who lack a family history of a similar illness, Leber's disease has been a diagnosis of exclusion. The recent discovery of a specific mitochondrial mutation in many pedigrees affected with the disease has provided the basis for rapid molecular diagnosis of one genetic type of Leber's disease. We have developed a new method, based on a Mae III (Boehringer Mannheim Biochemicals, Indianapolis, Ind) restriction fragment length polymorphism, for detecting the Wallace-type Leber's mutation. The method has several advantages over the previously used SfaN I method that make it more suitable for use as a general laboratory test. We demonstrate the utility of this new test in the diagnosis of Leber's disease in a patient with no family history of visual loss.