Diagnostic networks for IEM in Brazil: report on 10 years of activity of the LSD Brazil Network, helping Brazil and Latin America to identify patients with lysosomal storage diseases.

To contribute to the diagnosis of genetic metabolic diseases in Brazil, an innovative model of networks has been set up, aiming to provide information and testing of high-risk patients, free of charge, to doctors and services from Brazil and other countries. Particularly, our group set up the MPS (mucopolysaccharidoses), IEM (inborn errors of metabolism) and LSD (lysosomal storage diseases) networks. This paper describes the structure, services provided, and results obtained by the LSD Brazil Network (LBN) during its first 10 years of operation.The LBN has a core group that is responsible for the operation, guidance, logistics of sample collection and transportation, as well as test reports and information materials. The diagnostic investigation was performed in several laboratories affiliated to the program, all established in Porto Alegre, Brazil. The first ten years of operation of the LBN (2013-2022) were reviewed in detail. Over 10 years, 26,489 patients were investigated, and 27 LSDs were confirmed in 1,320 patients (4.98%). Comparing the first period of 5 years with the second one, there was a decrease in the number of requests, probably reflecting the impact of the COVID-19 pandemic. Interestingly, the same comparison indicated that there was an increase of 46% in the rate of diagnosis, possibly due to the improved selection of suspected cases. The model developed by the LBN, aiming to increase awareness and to remove barriers to diagnostic tests, suggests that the implementation of reference networks seems to be a suitable alternative to foster the diagnosis of LSDs, especially in developing countries, where resources and facilities are scarce.