ABCD1 and Adrenal insufficiency: Approximately 65% of these variants affect protein folding and stability, resulting in a marked reduction in ALDP from the peroxisome membrane.5 These mutants cause variable clinical symptoms, including adrenoleukodysfunction, adrenomyeloneurotrophy, and cerebral adrenoleukodystrophy.6–8 The early detection of adrenal insufficiency and cerebral ALD through newborn screening can help in the treatment of this disease.