In Leber's disease (LHON), degeneration of the optic nerve results in blindness due to a defect in NA dehydrogenase affecting electron transport. If this is due to a mutation in a mitochondrial gene, whi combination of the following effects would you expect to see when doing a pedigree analysis of a fa with LHON? i. variable expressivity
ii. incomplete penetrance
iii. progressive blindness over time
iv. maternal inheritance
v. diminished muscle mass

Question

Quizplus · Accepted Answer

Leber's Hereditary Optic Neuropathy (LHON) is a mitochondrial disorder, which explains the maternal inheritance pattern (iv) because mitochondria are inherited from the mother. The disease also shows variable expressivity (i) and incomplete penetrance (ii), meaning not everyone who inherits the mutation will exhibit symptoms or to the same degree. Progressive blindness over time (iii) is a characteristic symptom of LHON. However, diminished muscle mass (v) is not typically associated with LHON, so it is not included in the correct answer.

In Leber's Disease (LHON), Degeneration of the Optic Nerve Results