Investigation of newborns with abnormal results in a newborn screening program for four lysosomal storage diseases in Brazil.

Lysosomal storage diseases (LSDs) are genetic disorders, clinically heterogeneous, mainly caused by defects in genes encoding lysosomal enzymes that degrade macromolecules. Several LSDs already have specific therapies that may improve clinical outcomes, especially if introduced early in life. With this aim, screening methods have been established and newborn screening (NBS) for some LSDs has been developed. Such programs should include additional procedures for the confirmation (or not) of the cases that had an abnormal result in the initial screening. We present here the methods and results of the additional investigation performed in four babies with positive initial screening results in a program of NBS for LSDs performed by a private laboratory in over 10,000 newborns in Brazil. The suspicion in these cases was of Mucopolysaccharidosis I - MPS I (in two babies), Pompe disease and Gaucher disease (one baby each). One case of pseudodeficiency for MPS I, 1 carrier for MPS I, 1 case of pseudodeficiency for Pompe disease and 1 carrier for Gaucher disease were identified. This report illustrates the challenges that may be encountered by NBS programs for LSDs, and the need of a comprehensive protocol for the rapid and precise investigation of the babies who have an abnormal screening result.

Screening for Attenuated Forms of Mucopolysaccharidoses in Patients with Osteoarticular Problems of Unknown Etiology.

INTRODUCTION: The mucopolysaccharidoses (MPS) are a group of 11 inborn errors of metabolism (IEM) which are part of the lysosomal storage diseases (LSDs). The MPS are multisystemic conditions that affect the entire body, with variations in the clinical presentation, having specific treatments available depending on the type of MPS. Nearly all MPS disorders compromise the osteoarticular system in different ways, and virtually all patients have abnormal urinary excretion of glycosaminoglycans (GAGs). MPS are rare diseases that are underdiagnosed due to health-care professionals' lack of awareness, to poor access to screening and diagnostic methods, and to their extensive clinical heterogeneity. Attenuated forms may occur, which can make diagnosis of MPS even more difficult. METHODS: This study was conducted prospectively from March 2012 to January 2014 and included 55 patients at rheumatology and/or orthopedic services in Porto Alegre, Brazil. The screened patients presented with articular manifestations with no defined etiology. These patients were screened by quantitative and qualitative assessment of urinary GAGs. RESULTS AND DISCUSSION: Among the 55 cases investigated, one 15-year-old patient exhibited increased urinary GAG excretion; this patient was subsequently diagnosed with an attenuated form of MPS II, which was previously undetected. CONCLUSION: Although the proportion of patients with MPS identified in the study sample was small (1/55), this study shows that these diseases are underdiagnosed and that systematic screening can help identify patients who may benefit from specific treatments already available for several MPS types.

Identification of a novel missense mutation in Brazilian patient with a severe form of mucopolysaccharidosis type IVA.

Mucopolysaccharidosis type IVA (MPS IVA) or Morquio syndrome type A is an autosomal recessive disease caused by deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfatase (GALNS). We report molecular characterization of a patient who presents the new missense mutation p.C165Y in homozygosis. Bioinformatics analysis predicted this mutation as being probably pathogenic. To evaluate the possibility that this alteration was a polymorphism we tested 100 alleles and all the results were negative. These findings together with the observation that this alteration is not present in controls, suggest that it is a disease-causing mutation, which was correlated with the severe phenotype observed in our patient. We conclude that molecular analysis of the GALNS gene, in addition to enzyme assays, is important for diagnosis and contributes to the better understanding of the relationship between genotype and phenotype, which is important as enzyme replacement therapy (ERT) will soon become available and treatment decisions will have to be take in such cases.

Application of a protocol for the detection of disorders of sialic acid metabolism to 124 high-risk Brazilian patients.

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.

Genotoxicity of plant extracts

Aqueous extracts of seven species used in Brazilian popular medicine (Achyrocline satureoides, Iodina rhombifolia, Desmodium incanum, Baccharis anomala, Tibouchina asperior, Luehea divaricata, Maytenus ilicifolia) were screened to the presence of mutagenic activity in the Ames test (Salmonella/microsome). Positive results were obtained for A. satureoides, B anomala and L. divaricata with microsomal activation. As shown elsewhere (Vargas et al., 1990) the metabolites of A. satureoides extract also show the capacity to induce prophage and/or SOS response in microscreen phage induction assay and SOS spot chromotest.