In Leber's disease (LHON), degeneration of the optic nerve results in blindness due to a defect in NADH dehydrogenase affecting electron transport. If this is due to a mutation in a mitochondrial gene, which combination of the following effects would you expect to see when doing a pedigree analysis of a family 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, so it follows maternal inheritance. It often shows variable expressivity and incomplete penetrance, meaning not all individuals with the mutation will express the disease, and those who do may have varying severity. Progressive blindness is a characteristic symptom.

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