SPORADIC LEBER HEREDITARY OPTIC NEUROPATHY IN AUSTRALIA AND NEW-ZEALAND

Background: Leber hereditary optic neuropathy (LHON) is one of the mor e common forms of hered itary optic neuropathy and one of the few mito chondrial neuropathies. Prior to the advent of molecular DNA testing, the diagnosis depended on the recognition of typical fundal changes, a s well as a family history of maternal transmission. Sporadic cases we re therefore diagnosed with a level of uncertainty The aim of this stu dy is to identify the proportion of patients with idiopathic bilateral optic neuropathy/atrophy who are suffering from LHON. Methods: Reques ts were sent to all ophthalmologists and neurologist in Australia and New Zealand for blood or hair follicle samples of patients with diagno sis of bilateral optic neuropathy/atrophy of uncertain aetiology for D NA testing by restriction endonuclease analysis. Results: One hundred and fourty-four samples were received, of which 96 were sporadic cases of idiopathic optic atrophy. Eleven of these sporadic patients were f ound to harbour pathogenetic mitochondrial point mutations associated with LHON. Conclusions: Our results indicated that 11% of patients wit h bilateral optic neuropathy/atrophy of uncertain aetiology are suffer ing from LHON. Comparing this data with all the known familial cases o f LHON, we report that at least 8% of all LHON cases in Australia are sporadic. We concluded that mtDNA testing for LHON in patients with id iopathic optic atrophy should be included in the initial laboratory wo rk-up.