ACOX1 and Zellweger spectrum disorders: ACOX1 deficiency, previously known as pseudoneonatal adrenoleukodystrophy (ALD), is a rare and severe autosomal recessive disorder characterized by infantile-onset hypotonia, leukodystrophy, seizures, visual and hearing impairment, loss of motor achievements, and progressive gray matter degeneration [resembling Zellweger spectrum disorders (ZSDs)] (2, 3).