ABCD1 and adrenomyeloneuropathy: Genetic mutation in the ABCD1 gene leads to X-ALD, affecting very long chain fatty acid (VLCFA) processing (and resultant VLCFA buildup), which can manifest as several phenotypes, including adrenal insufficiency, adrenomyeloneuropathy (AMN), or a devasting demyelinating cerebral form, CALD, which occurs in up to 40% of young males with ALD before the age of 18 years [1].