This paper presents data collected by a Brazilian center in a multinational multicenter observational study of patients with mucopolysaccharidosis type VI (MPS VI), aiming at determining the epidemiological, clinical, and biochemical profile of these patients. Twenty-eight south-American patients with MPS VI were evaluated through medical interview, physical exam, echocardiogram, electrocardiogram, ophthalmologic evaluation, quantification of glycosaminoglycans (GAGs) in urine, and measurement of the activity of N-acetylgalactosamine-4-sulfatase (ARSB) in leukocytes. 92.9% of patients were Brazilian. Mean age at diagnosis and at evaluation was 48.4 months and 97.1 months, respectively. 88% of patients had onset of symptomatology before the age of 36 months. Consanguinity was reported by 27% of the families. Mean weight and height at birth were 3.481 kg and 51.3 cm, respectively. The most frequently reported clinical manifestations were short stature, corneal clouding, coarse facial features, joint contractures, and claw hands. All patients presented with echocardiogram changes as well as corneal clouding. Mean ARSB activity in leukocytes was 5.4 nmoles/h/mg protein (reference values: 72-174), and urinary excretion of GAGs was on average 7.9 times higher than normal. The number of clinical manifestations did not show a significant correlation with the levels of urinary GAGs nor with the ARSB activity. Also, no significant correlation was found between the levels of urinary GAGs and the ARSB activity. It was concluded that MPS VI has high morbidity and that, when compared with data published in the literature, patients in our study were diagnosed later and presented with a higher frequency of cardiological findings.

Mucopolysaccharidosis I (MPS I) is a lysosomal disorder characterized by a deficiency of the enzyme alpha-L: -iduronidase (IDUA), which is responsible for the degradation of glycosaminoglycans (GAGs). This deficiency leads to the accumulation of dermatan and heparan sulphate in lysosomes. Presently available treatments include bone marrow transplantation and enzyme replacement therapies, both of which are limited in their effects. In this work, knockout (KO) MPS I mice were treated with a nonviral vector containing the human IDUA cDNA. KO mice were transfected by hydrodynamic injection of pRIDUA in the caudal vein (i.v., n = 3) or by intraperitoneal injection of pRIDUA/Superfect complexes (i.p., n = 3). GAG concentration and IDUA activity were analysed in the kidneys, spleen, lungs, brain and liver. The expression of IDUA in the organs of i.v.- and i.p.-treated mice was also analysed by real-time reverse-transcription (RT) PCR and compared by relative quantification. The concentration of GAGs in the organs differed between KO and wild-type mice. In the spleen and liver, GAG levels were lower in i.v.- and i.p.-treated KO mice than in control nontreated animals. Real-time RT-PCR showed that the transgene is expressed in all the analysed organs of i.p.- and i.v.-treated KO mice. Enzyme activity was similarly observed in all the organs analysed. Our data suggest that this kind of transfection may be a useful tool for studies of nonviral protocols for gene therapy of MPS.

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Introduction: The advent of tyrosine kinase inhibitors has changed the natural history of chronic myelogenous leukemia (CML), promoting molecular remission in a high number of patients. In 40-60% of the patients that reach deep molecular responses (RM4.5 or more) and are using imatinib mesylate for 24 months or longer, a molecular response can be maintained after the cessation of the drug. Besides improving life quality in those patients, to withdraw the medication could have a great economic impact in the health system, what is extremely important in third world countries. Objective: To estimate the economic impact of stopping imatinib mesylate in CML chronic phase patients, receiving treatment for at least 36 months and presenting deep molecular response, determinate by BCR-ABL transcripts with quantitative reverse transcriptase polymerase chain reaction (QRT-PCR), in the last 24 months. Patients and methods: A single center observational retrospective study, including all patients diagnosed with chronic phase CML, confirmed by cytogenetic or molecular exams receiving treatment at a tertiary hospital in Brazil. All patients received imatinib mesylate either in first or second line therapy. Patients presenting deep molecular response for at least 24 months, under imatinib mesylate for 36 months or more were considered eligible for discontinuation the drug. The annual coast with the treatment was estimated considering the coasts of the medication and the QRT-PCR molecular exams in the Brazilian public health system. Results: In this study, 169 patients date were analyzed, the median follow up time is 5 years (range 1-13 years), 26 (15%) of those patients are eligible for stopping imatinib mesylate according to the criteria previously mentioned. Considering the requirement of QRT-PCR exams every month in the first year of discotinuating the drug, these patients would coast proximally 1.550,00 dollars/ patients year for the public health system. This coast could be reduced to 800,00 and 520 dollars/patients year, after the second and third year of the medication withdraw, when monitoring molecular response can be done every 2 and 3 months respectively. The patients receiving imatinib mesylate, and having QTR-PCR exams every six months, in the other hand, would coast the Brazilian public health system over 31.000, 00dollars /patients year. Stopping imatinib mesylate could reduce CML chronic phase treatment coasts in up to 95%. Discussion: Discontinuating imatinib mesylate is something that must be done only in clinical trial. The economic impact projection shown in this study observed the eligibility criteria described in the literature. If stopping imatinib mesylate proves to be a safe option, studies promoting it should be done in Brazil and other third world countries, as a manner of saving resources in the health system. Furthermore, the impact in life quality free of adverse effects and the possibility of gestation in young woman is not to be ignored. Disclosures No relevant conflicts of interest to declare.