Here goes for some random notes related to questions that I'm doing for the Step 1 exam.

Leigh disease: mitochondrial disorder also known as subacute necrotising encephalomyelopathy. Specific defect is cytochrome oxidase. Particularly affects muscle and brain, patients present in early adulthood, have progressive intellectual deterioriation, weakness, ataxia and siezures, then die within a few years. I'm not quite sure why they wait so long to present... but I'm not overly bothered either and am too lazy to look it up further!