Answer: The Leber's hereditary optic neuropathy (LHON) is caused by defective genes contained in mitochondrial DNA.
Explanation:
LHON is causes the vision loss. This occurs due to mutation in the mitochondrial DNA. The symptoms are not associated vision loss thus it is difficult to predict that which member of family was the carrier of the disease. Some people do not get completely blind. A young male is expected to develop a risk of 50% development of this disease.
psychological struggle within the mind of a literary or dramatic character, the resolution of which creates the plot's suspense: Hamlet's inaction is caused by internal conflict.