Relative frequency and estimated minimal frequency of Lysosomal Storage Diseases in Brazil: Report from a Reference Laboratory

Abstract Lysosomal storage diseases (LSDs) comprise a heterogeneous group of more than 50 genetic conditions of inborn errors of metabolism (IEM) caused by a defect in lysosomal function. Although there are screening tests for some of these conditions, diagnosis usually depends on specific enzyme assays, which are only available in a few laboratories around the world. A pioneer facility for the diagnosis of IEM and LSDs was established in the South of Brazil in 1982 and has served as a reference service since then. Over the past 34 years, samples from 72,797 patients were referred for investigation of IEM, and 3,211 were confirmed as having an LSD (4.41%, or 1 in 22), with 3,099 of these patients originating from Brazil. The rate of diagnosis has increased over time, in part due to the creation of diagnostic networks involving a large number of Brazilian services. These cases, referred from Brazilian regions, provide insight about the relative frequency of LSDs in the country. The large amount of data available allows for the estimation of the minimal frequency of specific LSDs in Brazil. The reported data could help to plan health care policies, as there are specific therapies available for most of the cases diagnosed.

Quantification of glucosylceramide in plasma of Gaucher disease patients

Gaucher disease is a sphingolipidosis that leads to an accumulation of glucosylceramide. The objective of this study was to develop a methodology, based on the extraction, purification and quantification of glucosylceramide from blood plasma, for use in clinical research laboratories. Comparison of the glucosylceramide content in plasma from Gaucher disease patients, submitted to enzyme replacement therapy or otherwise, against that from normal individuals was also carried out. The glucosylceramide, separated from other glycosphingolipids by high performance thin layer chromatography (HPTLC) was chemically developed (CuSO4 / H3PO4) and the respective band confirmed by immunostaining (human anti-glucosylceramide antibody / peroxidase-conjugated secondary antibody). Chromatogram quantification by densitometry demonstrated that the glucosylceramide content in Gaucher disease patients was seventeen times higher than that in normal individuals, and seven times higher than that in patients on enzyme replacement therapy. The results obtained indicate that the methodology established can be used in complementary diagnosis and for treatment monitoring of Gaucher disease patients.

A doença de Gaucher é uma esfingolipidose caracterizada pelo acúmulo de glicosilceramida. O objetivo deste estudo foi desenvolver metodologia baseada na extração, purificação e quantificação da glicosilceramida plasmática a qual possa ser usada em laboratórios de pesquisa clínica. Após o desenvolvimento desta metodologia, foi proposto, também, comparar o conteúdo de glicosilceramida presente no plasma de pacientes com doença de Gaucher, submetidos ou não a tratamento, com aquele de indivíduos normais. A glicosilceramida, separada de outros glicoesfingolipídios por cromatografia de camada delgada de alto desempenho (HPTLC), foi revelada quimicamente (CuSO4/H3PO4) e a respectiva banda foi confirmada por imunorrevelação (anticorpo anti-glicosilceramida humana/anticorpo secundário conjudado à peroxidase). A quantificação do cromatograma por densitometria demonstrou que o conteúdo de glicosilceramida nos pacientes com doença de Gaucher era 17 vezes maior que aquele de indivíduos normais e 7 vezes maior que aquele dos pacientes com doença de Gaucher submetidos a tratamento com terapia de reposição enzimática. Os resultados obtidos demonstram que a metodologia estabelecida pode ser usada como diagnóstico complementar e como monitoração do tratamento de pacientes com doença de Gaucher.