In Northern European populations about one in 9,000 people carries one of the three primary<unk>  mutations. There is a prevalence of between 1:30,000 to 1:50,000 in Europe. The<unk>  ND4 G11778A mutation is the primary mutation in most of the world, with 70% of Northern European cases and 90% of Asian cases. Due to a Founder effect, the<unk>  ND6 T14484C mutation accounts for 86% of<unk>  cases in Quebec, Canada. More than 50% of males with a mutation and more than 85% of females with a mutation never experience vision loss or related medical problems. The particular mutation type may predict the likelihood of penetrance, severity of illness and probability of vision recovery in the affected. As a rule of thumb, a woman who harbors a homoplasmic primary<unk>  mutation has a ~40% risk of having an affected son and a ~10% risk of having an affected daughter. Additional factors may determine whether a person develops the signs and symptoms of this disorder. Environmental factors such as smoking and alcohol use may be involved, though studies of these factors have produced conflicting results. Researchers are also investigating whether changes in additional genes, particularly genes on the X chromosome, contribute to the development of signs and symptoms. The degree of heteroplasmy, the percentage of mitochondria that have mutant alleles, may play a role. Patterns of mitochondrial alleles called haplogroup may also affect expression of mutations.
Leber's hereditary optic neuropathy
Kjer's optic neuropathy
Alexander disease
Graves' ophthalmopathy
Bosch-Boonstra-Schaaf optic atrophy syndrome
Sorsby's fundus dystrophy
Neuromyelitis optica spectrum disorder
Akureyri disease