[Hereditary optic nerve atrophy. A clinical-genealogical status over Danish families with Leber disease].

An update on Leber's hereditary optic neuropathy (LHON) in Denmark disclosed 32 families with at least one live affected member, or recent disease onset (Table 1). Mitochondrial DNA analysis in the 30 families available for blood sampling identified the pathogenic mutation in all of them: ND4/11778 (26 families), ND1/3460 (three families), and ND6/14484 (one family). A previous distinct male dominance (sex ratio 4.6:1 in 157 ND4-patients with onset before 1968) seems to level (sex ratio 2.6:1 in 69 ND4-patients with onset in 1968 or later). Among possible explanations, we discuss improved diagnostic abilities and possible changes in women's alcohol consumption and smoking habits.