Very Long Chain Fatty Acid Analysis of Dried Blood Spots on Filter Paper to Screen for Adrenoleukodystrophy

Abstract

Adrenoleukodystrophy (ALD) is an X-linked recessive disorder characterized by progressive demyelination of cerebral white matter and adrenal insufficiency. ALD is the most common peroxisomal disease, afflicting 1 in 20 000 male newborns. Patients with childhood ALD manifest changes of character or behavior and a decline of intelligence and visual or motor dysfunction as the first symptoms during school age. Most of them lapse into a vegetative state and die within several years of onset (1). Patients with all clinical subtypes, including childhood ALD, adolescent ALD, adult ALD (cerebral type), adrenomyeloneuropathy, and Addison disease without neurological symptoms, have defects in the ALD gene (2). Defective activity of peroxisomal lignoceroyl-CoA ligase is considered to lead to the accumulation of very long chain fatty acid (VLCFA) in various tissues and fluids as a secondary phenomenon (3)(4). Dietary erucic acid (C22:1) therapy may help prevent neurological deterioration in presymptomatic boys (5)(6). Patients in the early or presymptomatic stages may be candidates for bone marrow transplantation (5)(7). Gene therapy may also become possible. Screening for ALD, especially in the presymptomatic stage, will be important when these therapeutic methods are established, as in the cases of phenylketonuria or maple syrup urine disease. ALD is usually diagnosed by plasma VLCFA analysis (1)(8), sometimes followed by measurement of β-oxidation activity in cultured skin fibroblasts (9) and mutation analysis of the ALD gene (2)(10)(11)(12)(13)(14)(15)(16). However, screening requires a simpler and more economical method to deal with a large number of subjects. Utilization of a dried blood spot on filter paper …