Question
leber hereditary optic neuropathy (lhon) is a human disease that results from a mutation in the mitochondrial dna. it is characterized by a rapid loss of vision in both eyes, resulting from the death of cells in the optic nerve. assume that an affected man marries an unaffected woman. what proportion of their children is going to be affected with lhon?
Answer
None of their children will inherit LHON.
- Q:What is the mode of inheritance of LHON? A:LHON is a mitochondrial disorder which means that it is only passed down from the mother's side, because the egg contains the mitochondria.
- Q:If an affected man marries an unaffected woman (who doesn't carry the LHON mutation), what proportion of their children will inherit LHON? A:None of their children will inherit LHON. All of their children will be carriers of the mutation, but only the daughters will pass on the mutation to their children.
- Q:Why will none of their children inherit LHON? A:In the cross of an affected man and an unaffected woman, only the mother can pass on the mutation of LHON. The father does not pass on the affected mitochondrial DNA as the sperm does not contain the mitochondria.