What is Leber Hereditary Optic Neuropathy?

Leber Hereditary Optic Neuropathy (Lhon) is a form of progressive blindness. It is a genetic origin and is very rare. Symptoms usually occur for the first time when those who are affected for more than 10 years. This can happen in both eyes or only in one, although both eyes are usually affected. As the disease proceeds, the person develops problems that sees well enough to recognize other people with sight, drive a car or read. Color perception also deteriorates.

All these symptoms are due to the fact that the nerve that transmits visual data to the brain from the eyes slowly dying. In general, loss of vision does not cause any pain and sometimes vision can increase. However, some people who have Leber's hereditary optical neuropathy also have difficulty moving, have unpredictable hearts or develop multiple sclerosis. Four main genes include: MT-ND1, MT-ND4L, MT-ND4 and MT-ND6. All these genes are located in specific areas of human cells.

parts of cells that contain genes are called mitochondria. These are small structures that help cells produce usable energy from food. Most genetic information inside the cell is packed in another part of the cell, called core, but mitochondria also have small packets of genes.

normally genes involved in Lhon disease performs a major function for mitochondria. However, when one of these genes is mutated, the gene does not perform its work properly and the disease results. Since 2011, it has not been known exactly how individual abnormal genes have caused problems.

Every person in Herits mitochondria from his mother and none from the father. This is because the egg contains mitochondria, but not sperm. When an embryo is formed, it only has a mother's mitochondria, and therefore only mitochondrial genes of the mother.

Inheritance of one of the abnormal genes can therefore only come from the mother's side. In rare cases, one can have withPontane mutation in its genes that are not inherited. Not all people who have an abnormal gene will develop Leber's hereditary optical neuropathy, although the reasons are not known for this. Smoking, drinking alcohol, head injury or stress can be factors in determining the person developing this disease, but these causes have not been proven since 2011.