ABCD1 and adrenomyeloneuropathy: Loss of function of the ABCD1 gene can cause different phenotypes ranging from asymptomatic to adrenal insufficiency, adrenomyeloneuropathy (AMN) and an aggressive form of cerebral inflammatory demyelination (CALD) that leads to vegetative state or death within 2–5 years (Fig. 1A) (van Geel et al., 2001; Moser et al., 2005; Berger et al., 2014; Kemp et al., 2016).