Introduction

X-linked adrenoleukodystrophy (ALD) is the most common leukodystrophy with a birth incidence of 1 in 15.000 newborns. It is a progressive, “inborn error of metabolism” that affects brain, spinal cord, peripheral nerves, adrenal cortex and testis. ALD is caused by mutations in the ABCD1 gene. More than 800 unique mutations have been identified. For a comprehensive summary, please visit the Facts on ALD page.