We report a proband with Leber hereditary optic neuropathy (LHON), in whom we have identified a novel homoplasmic m.3,395A>G mutation in the ND1 gene. The mutation alters a highly conserved amino acid in codon 30 which previously has been associated with LHON and leads to a severe selective complex I deficiency. By providing further evidence for pathogenicity we conclude that m.3,395A>G is pathogenic. High definition optical coherence tomography of the retina and peripapillary retinal nerve fiber layer (pRNFL) confirms recent reports that retinal ganglion cell loss precedes axonal loss in LHON and is present in the early stage of the disease. Furthermore, evaluation of two unaffected mutation carriers disclosed asymptomatic borderline ganglion cell loss and thin pRNFL in one.
Keywords: Complex I deficiency; LHON; ND1 gene; leber hereditary optic neuropathy; mitochondrial DNA; optical coherence tomography; retinal ganglion cell; retinal nerve fiber layer.