ABSTRACT
X-linked adrenoleukodystrophy (X-ALD) is a genetically determined disorder that affects the nervous system, adrenal cortex, and testis. The defective gene, referred to as ABCD1, maps to Xq28, and codes for a peroxisomal membrane protein (ALDP) that is a member of the ATP binding cassette (ABC) transporter superfamily. X-ALD is associated with the abnormal accumulation of saturated very long chain fatty acids (VLCFA), such as hexacosanoic (C26:0) and tetracosanoic (C24:0) acids, in brain white matter, adrenal tissues, and plasma. The VLCFA excess is a diagnostic marker and may contribute to pathogenesis, but the pathogenetic mechanisms are complex and not yet understood. X-ALD affects approximately 1:21,000 males and 1:14,000 females are estimated to be heterozygous for X-ALD. It affects all ethnic groups with approximately the same frequency.
