I can't even remember the dz my question was asking about but the question was similar to this: "Pt. comes in after having normal development for the first 12 mos of life and then began to experience developmental delay. A cherry-red spot was observed on fundoscopic exam. Numerous neurological deficits were noted on PE. What organelle is most likely involved in the pathogenesis"
Lysosome was the most obvious answer. Kinda goes back to the whole "this test is all concepts" mantra everyone talks about. You might not even have to differentiate Niemann-Pick from Tay-Sachs, but knowing general concepts and symptoms related to LSD's is important. Knowing specifically that Fabry's causes kidney problems or that Niemann-Pick causes hepatosplenomegaly is less important if it comes at the expense of being comfortable with the concepts of LSD or most of the other high-yield concepts.