X-linked adrenoleukodystrophy: A biochemical cause of developmental regression in a seemingly well child

This case report outlines the diagnostic journey of a child with X-linked adrenoleukodystrophy (X-ALD) and discusses the prevalence, investigation and treatment of the condition. X-ALD is a rare condition, with a combined prevalence of heterozygotes and hemizygotes of about 1 in 17,000 children.1 It causes a peroxisomal fatty acid oxidation disorder that leads to inflammatory disease in the cerebral white matter. Patients may present with developmental arrest or regression and language difficulties, though this may be misidentified as an attention deficit disorder. Childhood manifestations of the disease are irreversible and may be insidious. Medical intervention may help to slow or halt disease progression, making rapid recognition and treatment key to a favourable outcome. Reference 1. Bezman L, Moser AB, Raymond GV, et al. Adrenoleukodystrophy: incidence, new mutation rate, and results of extended family screening. Ann Neurol 2001; 49: 512–7.