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