HTT and Huntington disease: Genetic mouse models of HD that transgenically overexpress mutant huntingtin accurately recapitulate the elevated levels of brain iron in the disease (Fox et al., 2007; Chen et al., 2013) and huntingtin knockdown in zebra fish models result in an iron deficiency phenotype (Hilditch-Maguire et al., 2000; Lumsden et al., 2007; Henshall et al., 2009).