NPC1 and Leukoencephalopathy: Amongst our putative risk genes from the ageing-associated TWAS analysis are EIF2B2, NPC1 and TUFM, which show leukodystrophy as a feature in people inheriting mutations of these genes (leukoencephalopathy with vanishing white matter, Niemann–Pick disease and combined oxidative phosphorylation deficiency 4, respectively).