RESUMO
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.
Assuntos
Hidrolases/metabolismo , Doenças por Armazenamento dos Lisossomos/diagnóstico , Lisossomos/enzimologia , Lisossomos/metabolismo , Coleta de Amostras Sanguíneas , Feminino , Humanos , Doenças por Armazenamento dos Lisossomos/enzimologia , Doenças por Armazenamento dos Lisossomos/metabolismo , Masculino , Programas de Rastreamento/métodosRESUMO
Gaucher disease (GD) is a sphingolipidosis caused by a genetic defect that leads to glucocerebrosidase (beta-glucosidase) deficiency. Between January 1982 and October 2003, 1,081 blood samples from patients suspected of having GD were referred for biochemical analysis. The activities of the enzymes beta-glucosidase (beta-glu) and chitotriosidase (CT) were measured in these samples. Among the 412 diagnosed cases of GD (38.1%), the great majority were GD type 1. The Brazilian regions with the greatest concentration of these patients were the Southeast, South, and Northeast. The mean age of patients at diagnosis was 19 years. The activity of beta-glu in patients with GD was, on average, 10.7% of that of normal individuals. CT was, on average, 269 times more elevated in this group of patients. Among the 669 cases with no confirmation of GD, there were patients with Niemann-Pick disease types A, B, or C (44 cases), possible heterozygotes for GD (59 cases), patients with other lysosomal storage diseases (LSDs) (19 cases) or with other inborn errors of metabolism (3 cases). In 508 cases, no metabolic disorder was found. This study shows that the biochemical protocol employed was effective for the detection of GD, a disease that is reasonably frequent in Brazil.
Assuntos
Doença de Gaucher/enzimologia , beta-Glucosidase/metabolismo , Adolescente , Adulto , Idoso , Brasil , Criança , Pré-Escolar , Feminino , Doença de Gaucher/diagnóstico , Doença de Gaucher/genética , Frequência do Gene , Genótipo , Geografia , Hexosaminidases/metabolismo , Humanos , Lactente , Doenças por Armazenamento dos Lisossomos/diagnóstico , Doenças por Armazenamento dos Lisossomos/enzimologia , Masculino , Pessoa de Meia-Idade , Mutação , Doenças de Niemann-Pick/diagnóstico , Doenças de Niemann-Pick/enzimologia , beta-Glucosidase/genéticaRESUMO
BACKGROUND: Gaucher's disease (GD) is a disorder caused by the deficiency of lysosomal beta-glucosidase, an enzyme that participates in the degradation of glycosphingolipids. Deficiency of this enzyme results in the accumulation of glucocerebrosides in macrophage lysosomes. No studies comparing the biochemical and kinetic behavior of this enzyme in leukocytes and fibroblasts from normal individuals and patients with Gaucher's disease are available. METHODS: We compared the activities of beta-glu and chitotriosidase between normal subjects and Gaucher disease patients, and characterized the behavior of beta-glu in terms of pH optimum, heat stability, Km and Vmax. RESULTS: The results showed a different behavior of the enzyme in the groups analyzed. CONCLUSIONS: This finding might be useful in cases in which the measurement of enzyme activity alone is not reliable for the establishment of the diagnosis of Gaucher's disease.
Assuntos
Doença de Gaucher/enzimologia , beta-Glucosidase/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Estabilidade Enzimática , Fibroblastos/enzimologia , Hexosaminidases/metabolismo , Homozigoto , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Cinética , Leucócitos/enzimologiaRESUMO
Lysosomal storage disorders (LSD) present great clinical variability. Included in this group are sialic acid metabolism disorders (SAMD). In the present study, we describe the application of a 3-step protocol for the diagnosis of SAMD, including (1). oligosaccharide and sialyloligosaccharide chromatography; (2). quantitative determination of sialic acid; and (3). measurement of neuraminidase activity. Application of our protocol to 124 individuals at risk for SAMD led to the diagnosis of five affected patients, two with type I sialidosis, one with type II sialidosis, and two with galactosialidosis. Due to its simplicity and efficiency, we propose the use of this protocol for the diagnostic evaluation of patients with suspected SAMD, which could be specially useful to non-specialized laboratories and to services located in developing countries.
