Transferrin isoelectric focusing for the investigation of congenital disorders of glycosylation: analysis of a ten-year experience in a Brazilian center / Isoeletrofocalização da transferrina para investigação das doenças congênitasda glicosilação: análise de dez anos de experiência de um centro brasileiro

Abstract Objectives: To characterize cases of suspected congenital disorders of glycosylation (CDG) investigated in a laboratory in southern Brazil using the transferrin isoelectric focusing TfIEF test from 2008 to 2017. Method: Observational, cross-sectional, retrospective study. The laboratory records of 1,546 individuals (median age = 36 months, 25-75 IQR = 10-108; males = 810) submitted to the TfIEF test during the period were reviewed. Results: Fifty-one individuals (3%) had an altered TfIEF pattern (5 ± 2.8 cases/year; median age = 24 months, 25-75 IQR = 11-57 months; males = 27, 53%). For 14 of them, data on diagnosis conclusion were available (classic galactosemia = 4; hereditary fructose intolerance = 4; peroxisomal diseases = 2; PMM2-CDG = 2; MPDU1-CDG = 1; SLC35A2-CDG = 1).Comparing the cases with the normal and altered TfIEF patterns, there was a higher prevalence of altered cases in the age group from 11 months to 3 years. There was an increase in the likelihood of change in TfIEF, especially in the presence of inverted nipples or liver disease. Conclusions: The data suggest that the investigation of a case with suspected CDG is a complex problem, being aggravated by the existence of other IEMs (inborn errors of metabolism) associated with altered TfIEF pattern and lack of access to confirmatory tests. The presence of inverted nipples and liver disease, especially in individuals aged 11 months to 3 years, should suggest the need for TfIEF investigation.

Resumo Objetivos: Caracterizar os casos com suspeita de CDG investigados em laboratório do sul do Brasil pelo exame de IEFTF de 2008 a 2017. Metodologia: Estudo observacional, transversal, retrospectivo. Foram revisadas as fichas laboratoriais de 1.546 indivíduos (mediana de idade = 36 meses, IQ 25-75 = 10-108; sexo masculino = 810) que fizeram o exame de IEFTF no período. Resultados: Cinquenta e um indivíduos (3%) apresentaram padrão alterado na IEFTF (5 ± 2,8 casos/ano; mediana de idade = 24 meses, IQ 25-75 = 11-57 meses; sexo masculino = 27, 53%). Para 14 deles, estavam disponíveis dados sobre a conclusão do diagnóstico (galactosemia clássica = 4; intolerância hereditária à frutose = 4; doenças peroxissomais = 2; PMM2-CDG = 2; MPDU1-CDG = 1; SLC35A2-CDG = 1). Comparando os casos com padrão normal e alterado na IEFTF, houve maior prevalência de casos alterados na faixa etária de 11 meses a 3 anos. Verificou-se um aumento na probabilidade de alteração na IEFTF principalmente na presença de mamilos invertidos ou de hepatopatia. Conclusões: Os nossos dados sugerem que a investigação de um caso com suspeita de CDG é complexa, é agravada pela existência de outros EIM associados a padrão alterado na IEFTF e pela falta de acesso a exames confirmatórios. A presença principalmente de mamilos invertidos e de hepatopatia em indivíduos na faixa etária de 11 meses a 3 anos deve sugerir a necessidade de investigação por IEFTF.

Monitoring of Phenylalanine Levels in Patients with Phenylketonuria Using Dried Blood Spots: a Comparison of Two Methods

Abstract Phenylketonuria (PKU) is caused by deficient activity of phenylalanine hydroxylase (PAH), responsible for the conversion of phenylalanine (Phe) to tyrosine (Tyr). Monitoring of patients with PKU requires the measurement of Phe in plasma using high-performance liquid chromatography (HPLC) or in dried blood spots (DBS) using different techniques to adjust treatment strategy. The objective of this study was to evaluate Phe levels in DBS measured by two different methods and compare them with Phe levels measured in plasma by HPLC. We analyzed 89 blood samples from 47 PKU patients by two different methods: fluorometric method developed in-house (method A) and the commercially available PerkinElmer® Neonatal Phenylalanine Kit (method B) and in plasma by HPLC. The mean Phe levels by method A, method B, and HPLC were 430.4±39.9μmol/L, 439.3±35.4μmol/L, and 442.2±41.6μmol/L, respectively. The correlation values between HPLC and methods A and B were 0.990 and 0.974, respectively (p < 0.001 for both). Our data suggest that methods A and B are useful alternatives for monitoring Phe levels in patients with PKU, with method A being in closer agreement with the reference standard (HPLC).

Long-term restoration of alpha-L-iduronidase activity in fibroblasts from patients with mucopolysaccharidosis type I after non-viral gene transfer

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by deficiency of alpha-L-iduronidase (IDUA). Limitations such as the need for weekly injections, high morbidity and mortality, and high cost of current treatments show that new approaches to treat this disease are required. In this study, we aimed to correct fibroblasts from a patient with MPS I using non-viral gene therapy. Using a plasmid encoding the human IDUA cDNA, we achieved stable high IDUA levels in transfected fibroblasts up to 6 months of treatment. These results serve as proof of concept that a non-viral approach can correct the enzyme deficiency in cells of patients with lysosomal storage disorders, which can be used as a research tool for a series of disease aspects. Future studies should focus on showing if this approach can be useful in small animals and clinical trials (AU)

Validation of a Multiplex Tandem Mass Spectrometry Method for the Detection of Selected Lysosomal Storage Diseases in Dried Blood Spots

Abstract Background: Interest in screening methods for lysosomal storage diseases (LSDs) has increased in recent years, since early diagnosis and treatment are essential to prevent or attenuate the onset of symptoms and the complications of these diseases. In the current work, we evaluated the performance of tandem mass spectrometry (MS/MS) for the detection of some LSDs, aiming the future use of this methodology for the screening of these disorders. Methods: Standard curves and quality control dried blood spots were assayed to evaluate the precision, linearity, and accuracy. A total of 150 controls were grouped according to age and subjected to measurement of lysosomal enzymes deficient in Niemann-Pick A/B, Krabbe, Gaucher, Fabry, Pompe, and Mucopolysaccharidosis type I diseases. Samples from 59 affected patients with a diagnosis of LSDs previously confirmed by fluorimetric methods were analyzed. Results: Data from standard calibration demonstrated good linearity and accuracy and the intra- and interassay precisions varied from 1.17% to 11.60% and 5.39% to 31.24%, respectively. Except for galactocerebrosidase and ?-l-iduronidase, enzyme activities were significantly higher in newborns compared to children and adult controls. Affected patients presented enzymatic activities significantly lower compared to all control participants. Conclusion: Our results show that MS/MS is a promising methodology, suitable for the screening of LSDs, but accurate diagnoses will depend on its correlation with other biochemical and/or molecular analyses.

Neurological outcomes after hematopoietic stem cell transplantation for cerebral X-linked adrenoleukodystrophy, late onset metachromatic leukodystrophy and Hurler syndrome / Desfechos neurológicos após transplante de células tronco hematopoiéticas na adrenoleucodistrofia ligada ao X, forma cerebral, na leucodistrofia metacromática de início tardio e na síndrome de Hurler

ABSTRACT Hematopoietic stem cell transplantation (HSCT) is the only available treatment for the neurological involvement of disorders such as late-onset metachromatic leukodystrophy (MLD), mucopolysaccharidosis type I-Hurler (MPS-IH), and X-linked cerebral adrenoleukodystrophy (CALD). Objective To describe survival and neurological outcomes after HSCT for these disorders. Methods Seven CALD, 2 MLD and 2 MPS-IH patients underwent HSCT between 2007 and 2014. Neurological examinations, magnetic resonance imaging, molecular and biochemical studies were obtained at baseline and repeated when appropriated. Results Favorable outcomes were obtained with 4/5 related and 3/6 unrelated donors. Two patients died from procedure-related complications. Nine transplanted patients were alive after a median of 3.7 years: neurological stabilization was obtained in 5/6 CALD, 1/2 MLD, and one MPS-IH patient. Brain lesions of the MPS-IH patient were reduced four years after HSCT. Conclusion Good outcomes were obtained when HSCT was performed before adulthood, early in the clinical course, and/or from a related donor.

RESUMO O transplante de células tronco hematopoiéticas (TCTH) é o único tratamento disponível para o envolvimento neurológico de doenças como a leucodistrofia metacromática (MLD), a mucopolissacaridose tipo I-Hurler (MPS-IH) e a adrenoleucodistrofia (CALD). Objetivos Descrever a sobrevida e os desfechos neurológicos após o TCTH nessas doenças. Métodos Sete pacientes CALD, 2 MLD e 2 MPS-IH realizaram TCTH entre 2007 e 2014. Avaliações neurológicas, ressonância nuclear magnética e estudos bioquímicos e moleculares foram feitos no baseline e repetidos quando apropriado. Resultados Desfechos favoráveis foram obtidos em 4/5 TCTH de doadores relacionados e em 3/6 não relacionados. Dois pacientes faleceram de complicações do procedimento. Nove transplantados sobreviveram após uma mediana de 3,7 anos: estabilização neurológica foi obtida em 5/6 CALD, ½ MLD e em um caso MPS-IH. As lesões encefálicas de um caso MPS-IH reduziram-se quatro anos após o TCTH. Conclusão Bons desfechos foram obtidos quando o TCTH foi feito antes da vida adulta, cedo no curso clínico e/ou a partir de um doador relacionado.

Early infantile form of galactosialidosis in a female baby with a prenatal diagnosis of fetal ascites - First case in Brazil

Apresentamos o primeiro caso de galactosialidose do tipo infantil precoce identificado entre a populaçäo brasileira, uma grave e rara doença de depósito lisossomal, com apenas 12 casos claramente descritos mundialmente. Estudos clínicos, patológicos e bioquímicos realizados foram consistentes com os dados já publicados na literatura científica. Detectamos a doença em uma menina de 7 meses de idade, com diagnóstico de ascite no período pré-natal e evoluçäo compatível com doença de depósito, através da cromatografia em camada fina para oligossacarídeos, que é parte integrante do programa de triagem para erros inatos do metabolismo (EIM) em crianças de alto risco, realizado no Estado do Rio de Janeiro.