Asymptomatic infants who are destined to die from metachromatic leukodystrophy (MLD), can be identified by urine positive for sulfatides. When detected early in life, bone marrow transplantation can provide, according to initial data, an effective, perhaps curative, treatment. Urine sulfatides of MLD patients are characteristic of this disease. Detection of sulfatides can be accomplished by using urine-soaked filter paper, a collection method used for mass screening of other diseases. Sulfatides from filter papers can be extracted and quantified by Continuous Flow-Fast Atom Bombardment- Mass Spectrometry and potentially, by electrospray/MS/MS. The Phase I grant will develop the process of extraction and quantification so that mass screening will be feasible. Three steps are planned: 1. Optimize conditions of the extraction of sulfatide and creatinine from urine-soaked filter papers. 2.Optimize conditions for the analysis of sulfatide by mass spectrometry. 3.Interface and automate the extraction and mass spectrometry methods. Phase II will involve screening of 75,000 specimens already collected and available. Phase III will screen 500,000 samples a year at specific sites. Introduction into several state departments of health procedures for screening will follow in the ensuing years, with payment derived from third party providers and state revenues.