Determination of the lysosomal hydrolase activity in blood collected on filter paper, an alternative to screen high risk populations.

This study aimed to determine the enzymatic activity in dried blood samples collected on filter paper (DBS) for the diagnosis of the following diseases: Fabry, Pompe, Mucopolysaccharidosis type I (MPS I) and Mucopolysaccharosis type VI (MPS VI). DBS was used for high risk patientscreening, according to clinical suspicion. Plasma, leukocytes and cultured fibroblasts were used to confirm the diagnosis when necessary. Among the 529 DBS samples sent to the laboratory, 164 had abnormal results. Confirmatory materials of 73 individuals were rerouted. The frequency of diagnosis for lysosomal storage disorders was 5.9%. DBS is an alternative screening technique used in high risk populations, which should lead to earlier diagnosis for lysosomal storage disorders (LSDs), help patients get treatment sooner and improve the outcome of the disease.