What is Leber's hereditary optic neuropathy (LHON)?
Leber's Hereditary Optic Neuropathy, or LHON, causes a painless loss of central vision in people with the condition when they’re between 12 and 30 years old. It’s associated with a mutation in mitochondrial DNA, which is inherited only from a child’s mother.
- LHON was the first human disease associated with a mutation in mitochondrial DNA.
- Both eyes are affected at the same time.
- Males will not pass the gene to any of their children, but females with the mutation will pass it to all of their children, regardless of whether they are sons or daughters.
What is mitochondrial inheritance?
The normal 46 chromosomes in our body are contained in the center of the cell, which is called the nucleus. Mitochondria are structures in the cell that are located outside of the nucleus in the cytoplasm and also contain genes that are separate from the ones in the nucleus.
Unlike nuclear genes, which are inherited from both parents, mitochondrial genes are inherited only from the mother. If there is a mutation in a mitochondrial gene, it’s passed from a mother to all of her children; sons won’t pass it on, but daughters will pass it on to all of their children.