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Introduction: Lysosomal storage disorders (LSD) are inherited diseases caused, in the majority of them, by the deficiency of lysosomal enzymatic activities. Ob-jectives: We aimed to analyze the usefulness of DBS samples for diagnosis of 4 LSDs, with the availability of a large quantity of patient samples. Design and methods: Blood samples from previously diagnosed patients with Fabry, Gaucher, Hunter, and Maro-teaux-Lamy syndromes and normal control individ-uals, were collected and dispen-sed in filter paper, and used for enzymatic activity determination. Results: Diagnosis of hemi/homo-zygous patients with Fabry, Hunter and Maroteaux-Lamy diseases using DBS samples showed ideal parameters of 100% sensitivity and specificity. DBS assay for Gaucher disease would need a posterior confirmatory step. Conclusions: Leukocyte measu-rement is the only reliable way to diagnose Gaucher disease. For Hunter, Fabry and Maroteaux-Lamy disorders discrimination between patients and controls seems adequate by DBS

FD was identified in 1 patient (.3%) in this first Latin American study. The patient presented with a late-onset oligo-symptomatic form of the disease. A large number of nonpathogenic mutations were present in our cohort, and it is essential that they not be mistaken for pathogenic mutations to avoid unnecessary enzyme replacement treatment.