The questions I've seen regarding diseases through two prep books that ask about the causes of diseases (Like Tay-Sachs, Sickle Cell, etc.). More often than not the answer is genetic for these types of questions.
I've seen one question that has asked "Which disease occurs because of a disorder in amino acid metabolism?" The answer was Phenylketonuria...
I've also seen a question that has asked what are are the sec chromosomes of someone with Kleinfelter's Syndrome, which is XXY.
In general though, I wouldn't spend too much time at all trying to go over diseases in depth. I doubt we would need to know the mechanisms of a disease, and since I have seen so few of these questions in my practice books, I doubt there will be more than one or two, if any, on the actual test. I would just memorize the diseases you come across in your practice and just leave it at that. Otherwise you'd be trying to memorize an insane amount of information.
