Leber Hereditary Optic Neuropathy (LHON) is a rare, degenerative disease of the optic nerve characterized by progressive and painless vision loss. It usually occurs between the ages of 15 and 30 and, for unknown reasons, it affects males more frequently.
In the context of hereditary diseases and, in particular, of rare hereditary diseases, the mutations that trigger the disease represent the most important data, the ones first reported on the “identity card” of the pathology.
Usually, these mutations are a lot and are hidden in different genes, therefore it is essential to identify them all: in fact, with the understanding of the genotype, it is easier to apply a targeted and more effective treatment.
Leber Hereditary Optic Neuropathy (LHON) is caused by mutations in the mitochondrial DNA, inherited from the mother.
The disease mainly affects men and can lead to permanent blindness.
The Causes of LHON
Leber Hereditary Optic Neuropathy is an inherited disease caused by mutations in the mitochondrial DNA.
Mitochondria are cellular organelles, with their own DNA, essential for the production of the energy needed by cells. Over time, more than 20 disease-causing mutations have been identified and the main ones produce defects in the genes of the Complex I subunit of the mitochondrial respiratory chain (MT-ND1, MT-ND4, and Mt-ND6).
Like all mitochondrial diseases, Leber optic neuropathy can only be transmitted to the offspring from the mother as the sperms do not carry mitochondria with them at the time of fertilization.
Symptoms of LHON
The first noticeable symptoms are made up of visual fogging with a subsequent decrease in central vision and color perception.
The two eyes can be affected simultaneously or in rapid succession; it happens that other symptoms and signs described as Leber ‘plus’ are associated.
These may include motor disturbances, dystonia, postural tremor, cerebellar ataxia, and impaired cardiac conduction.
In some cases, patients manifest muscle weakness, poor coordination, and sensitivity associated with multiple sclerosis.
Therapy
To date, there is no cure for Leber Hereditary Optic Neuropathy.
However, there are visual aids and rehabilitation therapies.
Central vision may gradually improve, however in most cases, the vision loss is severe and permanent.