Twenty years of Colombian experience with enzymatic screening in patients with features of mucopolysaccharidosis.

Mucopolysaccharidoses (MPSs) are a group of genetic alterations whose effect is the progressive intralysosomal accumulation of glycosaminoglycans. Affected individuals are deficient in one or more lysosomal enzymes which, depending on the MPS, may cause coarse facial features, short stature, multiple skeletal dysplasia, joint stiffness, or developmental delay. Their diagnosis is mostly performed late or incorrectly, and it represents a challenge since it requires specialized tests only performed in major cities. This makes it difficult for patients to have access to physicians since their geographical location is distant and therefore, the use of samples collected in solid-phase represents an advantage for the study of high-risk populations. In addition, epidemiological information about rare diseases, especially in Latin America, is scarce or inconsistent. Our aim was to report the experience of 20 years of selective screening by assessing enzyme activity and reporting incidence values of MPS in Colombia. This study validated a group of fluorometric endpoint techniques in 8239 patients. The samples were dried blood spots (DBS) collected on filter paper and leukocyte extracts. Reference values in the Colombian population for α-l-iduronidase, iduronate 2-sulfatase, α-N-acetylglucosaminidase, N-acetylglucosamine-6-sulfate sulfatase, ß-galactosidase, arylsulfatase B, and ß-glucuronidase were established in leukocyte extracts, and patients reference ranges were updated in the case of DBS samples. Incidence values were calculated for each MPS and the distribution of cases across the country is also shown. This study offers very useful information for the health system, the scientific community, and it facilitates the diagnosis of these disorders. This is indispensable when seeking to develop new diagnostic or treatment approaches for patients.

Leucodistrofia metacromática del adulto: reporte de caso / Adult-onset metachromatic leukodystrophy

RESUMEN INTRODUCCIÓN: La leucodistrofia metacromática (LDM) es una enfermedad poco frecuente que se caracteriza por desmielinización progresiva a nivel del sistema nervioso central y periférico. En la mayoría de los casos, es causada por una actividad deficiente de la enzima arilsulfatasa-A. Pertenece al grupo de las leucodistrofias, que son trastornos hereditarios de la sustancia blanca asociados con una variabilidad fenotípica y una heterogeneidad genética importante. El fenotipo de la LDM suele relacionarse con la edad de presentación, que puede variar desde la infancia hasta la adultez. Cuando se presenta en la edad adulta, puede debutar con manifestaciones neuropsiquiátricas, lo que lleva con frecuencia a diagnósticos erróneos. REPORTE DE CASO: Se presenta el caso de una paciente adulta que debutó con un cuadro clínico caracterizado por cambios comportamentales progresivos, con posterior inicio de manifestaciones clínicas motoras. El diagnóstico de LDM se sospechó a partir de la clínica y los hallazgos típicos en la resonancia magnética (RM) cerebral, y se confirmó con la detección de actividad deficiente de la arilsulfatasa-A (ARSA) y la secuenciación del gen ARSA que confirmó la mutación en estado homocigoto, compatible con este diagnóstico. DISCUSIÓN: Destacamos en este caso la importancia de la sospecha clínica, el reconocimiento temprano y el manejo multidisciplinario como factores pronósticos del curso de la enfermedad, ya que en la actualidad no hay tratamiento definitivo para la enfermedad.

ABSTRACT INTRODUCTION: Metachromatic leukodystrophy (MLD) is an infrequent disease characterized by progressive demyelination of the central and peripheral nervous system. In most cases, it is caused by deficient activity of arylsulfatase-A. It belongs to the group of leukodystrophies, which are inherited white matter disorders that can be associated with significant phenotypic variability and genetic heterogeneity. The phenotype in MLD is usually related to the age of onset, which can vary from childhood to adulthood. Adult-onset MLD can debut with neuropsychiatry symptoms, which can often lead to misdiagnosis. CASE REPORT: We report the case of an adult female patient who presented with progressive behavioral changes, followed by motor manifestations. MLD was initially suspected based on the clinical presentation and the characteristic findings on brain magnetic resonance imaging (MRI), with subsequent confirmation by detection of deficient arylsulfatase-A (ARSA) activity and ARSA gene sequencing, which demonstrated homozygosity, compatible with this diagnosis. DISCUSSION: We highlight the importance of clinical suspicion, early recognition and multidisciplinary management as a prognostic factor for the course of the disease, since there is currently no definitive treatment for the disease.

Enzyme Replacement Therapy with Pabinafusp Alfa for Neuronopathic Mucopolysaccharidosis II: An Integrated Analysis of Preclinical and Clinical Data.

Enzyme replacement therapy (ERT) improves somatic manifestations in mucopolysaccharidoses (MPS). However, because intravenously administered enzymes cannot cross the blood-brain barrier (BBB), ERT is ineffective against the progressive neurodegeneration and resultant severe central nervous system (CNS) symptoms observed in patients with neuronopathic MPS. Attempts to surmount this problem have been made with intrathecal and intracerebroventricular ERT in order to achieve CNS effects, but the burdens on patients are inimical to long-term administrations. However, since pabinafusp alfa, a human iduronate-2-sulfatase fused with a BBB-crossing anti-transferrin receptor antibody, showed both central and peripheral efficacy in a mouse model, subsequent clinical trials in a total of 62 patients with MPS-II (Hunter syndrome) in Japan and Brazil substantiated this dual efficacy and provided an acceptable safety profile. To date, pabinafusp alfa is the only approved intravenous ERT that is effective against both the somatic and CNS symptoms of patients with MPS-II. This article summarizes the previously obtained preclinical and clinical evidence related to the use of this drug, presents latest data, and discusses the preclinical, translational, and clinical challenges of evaluating, ameliorating, and preventing neurodegeneration in patients with MPS-II.

Genotype-phenotype studies in a large cohort of Brazilian patients with Hunter syndrome.

Mucopolysaccharidosis type II (MPS II) is an X-linked inherited disease caused by pathogenic variants in the IDS gene, leading to deficiency of the lysosomal enzyme iduronate-2-sulfatase and consequent widespread storage of glycosaminoglycans, leading to several clinical consequences, with progressive manifestations which most times includes cognitive decline. MPS II has wide allelic and clinical heterogeneity and a complex genotype-phenotype correlation. We evaluated data from 501 Brazilian patients diagnosed with MPS II from 1982 to 2020. We genotyped 280 of these patients (55.9%), which were assigned to 206 different families. Point mutations were present in 70% of our patients, being missense variants the most frequent. We correlated the IDS pathogenic variants identified with the phenotype (neuronophatic or non-neuronopathic). Except for two half-brothers, there was no discordance in the genotype-phenotype correlation among family members, nor among MPS II patients from different families with the same single base-pair substitution variant. Mothers were carriers in 82.0% of the cases. This comprehensive study of the molecular profile of the MPS II cases in Brazil sheds light on the genotype-phenotype correlation and helps the better understanding of the disease and the prediction of its clinical course, enabling the provision of a more refined genetic counseling to the affected families.

Iduronate-2-sulfatase fused with anti-hTfR antibody, pabinafusp alfa, for MPS-II: A phase 2 trial in Brazil.

In Hunter syndrome (mucopolysaccharidosis II [MPS-II]), systemic accumulation of glycosaminoglycans (GAGs) due to a deficiency of iduronate-2-sulfatase (IDS), caused by mutations in the IDS gene, leads to multiple somatic manifestations and in patients with the severe (neuronopathic) phenotype, also to central nervous system (CNS) involvement. These symptoms cannot be effectively treated with current enzyme-replacement therapies, as they are unable to cross the blood-brain barrier (BBB). Pabinafusp alfa, a novel IDS fused with an anti-human transferrin receptor antibody, was shown to penetrate the BBB and to address neurodegeneration in preclinical studies. Subsequent phase 1/2 and 2/3 clinical studies in Japan have shown marked reduction of GAG accumulation in the cerebrospinal fluid (CSF), along with favorable clinical responses. A 26-week, open-label, randomized, parallel-group phase 2 study was conducted in Brazil to further evaluate the safety and efficacy of intravenously administered pabinafusp alfa at 1.0, 2.0, and 4.0 mg/kg/week in MPS-II patients. The safety profiles in the three dosage groups were similar. Neurodevelopmental evaluation suggested positive neurocognitive signals despite a relatively short study period. The 2.0-mg/kg group, which demonstrated marked reductions in substrate concentrations in the CSF, serum, and urine, was considered to provide the best combination regarding safety and efficacy signals.

Testicular steroid sulfatase overexpression is associated with Leydig cell dysfunction in primary spermatogenic failure.

BACKGROUND: Decreased testosterone (T) to LH ratio and increased 17ß-estradiol (E2) serum concentrations represent a common finding among patients with severe spermatogenic failure, suggesting a concurrent Leydig cell steroidogenic dysfunction. Aromatase overexpression has been associated with increased serum and intratesticular E2 in these patients. However, it is unknown whether the sulfatase pathway contributes to the increased availability of active estrogens in patients with primary spermatogenic failure. OBJECTIVES: To assess estrogen sulfotransferase (SULT1E1) and steroid sulfatase (STS) mRNA abundance in testicular tissue of patients with Sertoli cell-only syndrome (SCOS) and normal tissues, its association with serum and intratesticular hormone levels, and to explore the mRNA and protein testicular localization of both enzymes. MATERIALS AND METHODS: Testicular tissues of 23 subjects with SCOS (cases) and 22 patients with obstructive azoospermia and normal spermatogenesis (controls) were obtained after biopsy. SULT1E1 and STS transcripts accumulation was quantified by RT-qPCR. For mRNA and protein localization, we performed RT-qPCR in Leydig cell clusters and seminiferous tubules isolated by laser-capture microdissection and immunofluorescence in testicular tissues. Serum and intratesticular hormones were measured by immunoradiometric assays. RESULTS: SULT1E1 mRNA accumulation was similar in both groups. The amount of STS mRNA was higher in cases (p = 0.007) and inversely correlated with T/LH ratio (r = -0.402; p = 0.02). Also, a near significant correlation was observed with intratesticular E2 (r = 0.329, p = 0.057), in agreement with higher intratesticular E2 in cases (p < 0.001). Strong STS immunoreaction was localized in the wall of small blood vessels but not in Leydig cells. Both SULT1E1 and STS mRNA abundance was similar in Leydig cell clusters and the tubular compartment, except for lower SUTL1E1 mRNA in the seminiferous tubules of SCOS patients (p = 0.001). CONCLUSIONS: Our results suggest that an unbalance of the STS/SULT1E1 pathway contributes to the testicular hyperestrogenic microenvironment in patients with primary spermatogenic failure and Leydig cell dysfunction.

Therapeutic Options for Mucopolysaccharidosis II (Hunter Disease).

BACKGROUND: Mucopolysaccharidosis type II (Hunter syndrome, or MPS II) is an X-linked lysosomal disorder caused by the deficiency of iduronate-2-sulfatase, which leads to the accumulation of glycosaminoglycans (GAGs) in a variety of tissues, resulting in a multisystemic disease that can also impair the central nervous system (CNS). OBJECTIVE: This review focuses on providing the latest information and expert opinion about the therapies available and under development for MPS II. METHODS: We have comprehensively revised the latest studies about hematopoietic stem cell transplantation (HSCT), enzyme replacement therapy (ERT - intravenous, intrathecal, intracerebroventricular, and intravenous with fusion proteins), small molecules, gene therapy/genome editing, and supportive management. RESULTS AND DISCUSSION: Intravenous ERT is a well-established specific therapy, which ameliorates the somatic features but not the CNS manifestations. Intrathecal or intracerebroventricular ERT and intravenous ERT with fusion proteins, presently under development, seem to be able to reduce the levels of GAGs in the CNS and have the potential of reducing the impact of the neurological burden of the disease. Gene therapy and/or genome editing have shown promising results in preclinical studies, bringing hope for a "one-time therapy" soon. Results with HSCT in MPS II are controversial, and small molecules could potentially address some disease manifestations. In addition to the specific therapeutic options, supportive care plays a major role in the management of these patients. CONCLUSION: At this time, the treatment of individuals with MPS II is mainly based on intravenous ERT, whereas HSCT can be a potential alternative in specific cases. In the coming years, several new therapy options that target the neurological phenotype of MPS II should be available.

Population-Based Newborn Screening for Mucopolysaccharidosis Type II in Illinois: The First Year Experience.

OBJECTIVES: To assess the outcome of population-based newborn screening for mucopolysaccharidosis type II (MPS II) during the first year of screening in Illinois. STUDY DESIGN: Tandem mass spectrometry was used to measure iduronate-2-sulfatase (I2S) activity in dried blood spot specimens obtained from 162 000 infant samples sent to the Newborn Screening Laboratory of the Illinois Department of Public Health in Chicago. RESULTS: One case of MPS II and 14 infants with pseudodeficiency for I2S were identified. CONCLUSIONS: Newborn screening for MPS II by measurement of I2S enzyme activity was successfully integrated into the statewide newborn screening program in Illinois.

A New Mutation in IDS Gene Causing Hunter Syndrome: A Case Report.

RATIONALE: Mucopolysaccharidosis type II (Hunter syndrome) is an X-linked multisystem disorder, caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase (I2S). The clinical manifestations of this disease are severe skeletal deformities, airway obstruction, cardiomyopathy, and neurologic deterioration. PATIENT: The patient was 5 years and 6 months boy, with developmental delay, hearing loss, hepatosplenomegaly, and skeletal dysplasia. He was diagnosed with mucopolysaccharidosis type II based on clinical manifestations, biochemical and genetic analysis. OUTCOMES: The patient carries a new mutation (c.879-1210_1007-218del) in hemizygosis in the IDS gene, which was defined as pathogenic according to the 2015 American College of Medical Genetics and Genomics-Association for Molecular Pathology guidelines and as responsible for the mucopolysaccharidosis type II phenotype in the patient.

Production and characterization of a human lysosomal recombinant iduronate-2-sulfatase produced in Pichia pastoris.

Hunter syndrome (Mucopolysaccharidosis II, MPS II) is an X-linked lysosomal storage disease produced by the deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS). Currently, MPS II patients are mainly treated with enzyme replacement therapy (ERT) using recombinant enzymes produced in mammalian cells. As an alternative, several studies have shown the production of active and therapeutic forms of lysosomal proteins in microorganisms. In this paper, we report the production and characterization of a recombinant IDS produced in the yeast Pichia pastoris (prIDS). We evaluated the effect of culture conditions and gene sequence optimization on prIDS production. The results showed that the highest production of prIDS was obtained at oxygen-limited conditions using a codon-optimized IDS cDNA. The purified enzyme showed a final activity of 12.45 nmol mg-1 H-1 and an apparent molecular mass of about 90 kDa. The highest stability was achieved at pH 6.0, and prIDS also showed high stability in human serum. Noteworthy, the enzyme was taken up by culture cells in a dose-dependent manner through mannose receptors, which allowed the delivery of the enzyme to the lysosome. In summary, these results show the potential of Pichia pastoris as a host to produce an IDS intended for a MPS II ERT.

Hematopoietic Stem Cell Transplantation for Patients with Mucopolysaccharidosis II.

There is limited information regarding the long-term outcomes of hematopoietic stem cell transplantation (HSCT) for mucopolysaccharidosis II (MPS II). In this study, clinical, biochemical, and radiologic findings were assessed in patients who underwent HSCT and/or enzyme replacement therapy (ERT). Demographic data for 146 HSCT patients were collected from 27 new cases and 119 published cases and were compared with 51 ERT and 15 untreated cases. Glycosaminoglycan (GAG) levels were analyzed by liquid chromatography tandem mass spectrometry in blood samples from HSCT, ERT, and untreated patients as well as age-matched controls. Long-term magnetic resonance imaging (MRI) findings were investigated in 13 treated patients (6 ERT and 7 HSCT). Mean age at HSCT was 5.5 years (range, 2 to 21.4 years) in new patients and 5.5 years (range, 10 months to 19.8 years) in published cases. None of the 27 new patients died as a direct result of the HSCT procedure. Graft-versus-host disease occurred in 8 (9%) out of 85 published cases, and 9 (8%) patients died from transplantation-associated complications. Most HSCT patients showed greater improvement in somatic features, joint movements, and activity of daily living than the ERT patients. GAG levels in blood were significantly reduced by ERT and levels were even lower after HSCT. HSCT patients showed either improvement or no progression of abnormal findings in brain MRI while abnormal findings became more extensive after ERT. HSCT seems to be more effective than ERT for MPS II in a wide range of disease manifestations and could be considered as a treatment option for this condition.

Oxidative profile exhibited by Mucopolysaccharidosis type IVA patients at diagnosis: Increased keratan urinary levels.

Morquio A disease (Mucopolysaccharidosis type IVA, MPS IVA) is one of the 11 mucopolysaccharidoses (MPSs), a heterogeneous group of inherited lysosomal storage disorders (LSDs) caused by deficiency in enzymes need to degrade glycosaminoglycans (GAGs). Morquio A is characterized by a decrease in N-acetylgalactosamine-6-sulfatase activity and subsequent accumulation of keratan sulfate and chondroitin 6-sulfate in cells and body fluids. As the pathophysiology of this LSD is not completely understood and considering the previous results of our group concerning oxidative stress in Morquio A patients receiving enzyme replacement therapy (ERT), the aim of this study was to investigate oxidative stress parameters in Morquio A patients at diagnosis. It was studied 15 untreated Morquio A patients, compared with healthy individuals. The affected individuals presented higher lipid peroxidation, assessed by urinary 15-F2t-isoprostane levels and no protein damage, determined by sulfhydryl groups in plasma and di-tyrosine levels in urine. Furthermore, Morquio A patients showed DNA oxidative damage in both pyrimidines and purines bases, being the DNA damage positively correlated with lipid peroxidation. In relation to antioxidant defenses, affected patients presented higher levels of reduced glutathione (GSH) and increased activity of glutathione peroxidase (GPx), while superoxide dismutase (SOD) and glutathione reductase (GR) activities were similar to controls. Our findings indicate that Morquio A patients present at diagnosis redox imbalance and oxidative damage to lipids and DNA, reinforcing the idea about the importance of antioxidant therapy as adjuvant to ERT, in this disorder.

A structural appraisal of sterol carrier protein 2.

Sterol Carrier Protein 2 (SCP2) has been associated with lipid binding and transfer activities. However, genomic, proteomic, and structural studies revealed that it is an ubiquitous domain of complex proteins with a variety functions in all forms of life. High-resolution structures of representative SCP2 domains are available, encouraging a comprehensive review of the structural basis for its success. Most SCP2 domains pertain to three major families and are frequently found as stand-alone or at the C-termini of lipid related peroxisomal enzymes, acetyltransferases causing bacterial resistance, and bacterial environmentally important sulfatases. We (1) analyzed the structural basis of the fold and the classification of SCP2 domains; (2) identified structure-determined sequence features; (3) compared the lipid binding cavity of SCP2 and other lipid binding proteins; (4) surveyed proposed mechanisms of SCP2 mediated lipid transfer between membranes; and (5) uncovered a possible new function of the SCP2 domain as a protein-protein recognition device.

Impact of Elosulfase Alfa on Pain in Patients with Morquio A Syndrome over 52 Weeks: MOR-008: A Randomized, Double-Blind, Pilot Study

Abstract Patients with mucopolysaccharidosis (MPS), and Morquio A syndrome (MPS IVA) in particular, often report substantial pain burden. MOR-008 was a randomized, double-blind, pilot study assessing the safety and efficacy, including impact on patient-reported pain, of 52 weeks of treatment with elosulfase alfa (at a dose of 2.0 or 4.0 mg/kg/week) in patients with Morquio A syndrome (?7 years old). Assessment of pain at baseline revealed that patients (N = 25) had a mean number of pain locations of 5.7, mean pain intensity score of 4.6 (indicative of medium pain), and a mean number of selected pain descriptors of 7.4 words. Treatment with elosulfase alfa improved subjective pain score (reduced to 3.2), pain locations (reduced by a mean of 1 location), and pain descriptor words (reduced to 4.9 words) over 1 year (52 weeks), suggesting that elosulfase alfa can reduce pain in some patients with Morquio A.

Cost-Effectiveness of the Quantification of Enzymatic Activity in Leukocytes in Comparison to Its Nonrealization for a Rare Disease in Latin America: The Case of Mucopolysaccharidosis Type II in Colombia.

BACKGROUND: Mucopolysaccharidosis (MPS) type II is produced by a deficiency of iduronate-2-sulfatase (I2S). The quantification of the enzyme activity in leukocytes is used as diagnostic confirmation of MPS. OBJECTIVE: To determinate the cost-effectiveness of the measurement of I2S enzyme activity in leukocytes compared with not carrying out the enzyme activity measurement for diagnostic confirmation of MPS II from the perspective of the Colombian health system. METHODS: A cost-effectiveness analysis was conducted on the basis of a decision tree model. The measure of effectiveness was the correct diagnosis of cases of MPS II. The costs of I2S enzymatic quantification in leukocytes, consultation with a geneticist and with other specialists, and costs of diagnostic procedures were included. The time horizon was less than 1 year. A probabilistic sensitivity analysis was performed using Monte-Carlo simulation with 10,000 iterations. RESULTS: The incremental cost was -US $43,145 with an incremental effectiveness of 42 cases. The probabilistic sensitivity analysis confirms the results of basal data, in which the quantification of I2S enzyme activity was less costly and more effective than the alternative. CONCLUSIONS: The quantification of I2S enzymatic activity is a dominant technology for the diagnostic confirmation of MPS II, compared with not making the quantification, from the perspective of the Colombian health system.

Mucopolysaccharidosis type VI on enzyme replacement therapy since infancy: Six years follow-up of four children.

Clinical and biochemical improvements are reported on Mucopolysaccharidosis type VI (MPS VI) patients on Enzyme Replacement Therapy (ERT) with rhASB (galsulfase, Naglazyme®), and preclinical and clinical studies have shown clinical benefits of early initiation. We report four unrelated MPS VI children who began ERT as infants (ages 5 days­10 months). The three older patients showed the first clinical signs of MPS VI at baseline, also presenting different degrees of dysostosis multiplex, and two had mild heart disease. The two oldest also had mild facial coarseness, one had hearing conduction deficit and sleep disorder and the other corneal clouding at baseline. After six years on ERT, all four patients have normal urinary GAG values. Although they all showed normal motor and mental development, brain and cervical spine MRI images available from two of the older patients showed abnormalities, while the youngest child continues having normal images. The four patients presented slower progression of bone and joint disease when compared to their affected older siblings. It should be noticed that only two patients in this sample are currently below the 3rd percentile for height: the youngest who has a constitutional factor associated and the eldest who already presented frank dysostosis at 10 months of age. These findings confirm previous studies that report that skeletal features of the disease cannot be completely prevented despite early ERT. Heart disease already present in two of the four infants at baseline got worse over time and appeared in another patient, but the youngest child on ERT introduction still has a normal echocardiogram at six years of age; he also is the only one without corneal clouding after six years follow-up. Our results also suggest that early ERT prevented storage in spleen and liver and may also have improved or prevented progression of facial dysmorphic features, corroborating similar findings seen in previous studies. No safety concerns were identified and none of the patients experienced a serious adverse event. The baseline severity of the disorder of these four infants seems related to age and it is tempting to say that severity on the first year of life is progressive and ERT effectiveness is indirectly related to it. Despite being known that MPS VI progresses differently among patients, the fact that these infants had a slower progression than their older siblings speaks in favor of a very early start of ERT. In conclusion, this report confirms the early manifestations of the disease and provides additional evidence on safety and of the beneficial effects of ERT in patients less than 1 year of age.

Guidelines for diagnosis and treatment of Hunter Syndrome for clinicians in Latin America.

This review aims to provide clinicians in Latin America with the most current information on the clinical aspects, diagnosis, and management of Hunter syndrome, a serious and progressive disease for which specific treatment is available. Hunter syndrome is a genetic disorder where iduronate-2-sulfatase (I2S), an enzyme that degrades glycosaminoglycans, is absent or deficient. Clinical manifestations vary widely in severity and involve multiple organs and tissues. An attenuated and a severe phenotype are recognized depending on the degree of cognitive impairment. Early diagnosis is vital for disease management. Clinical signs common to children with Hunter syndrome include inguinal hernia, frequent ear and respiratory infections, facial dysmorphisms, macrocephaly, bone dysplasia, short stature, sleep apnea, and behavior problems. Diagnosis is based on screening urinary glycosaminoglycans and confirmation by measuring I2S activity and analyzing I2S gene mutations. Idursulfase (recombinant I2S) (Elaprase(®), Shire) enzyme replacement therapy (ERT), designed to address the underlying enzyme deficiency, is approved treatment and improves walking capacity and respiratory function, and reduces spleen and liver size and urinary glycosaminoglycan levels. Additional measures, responding to the multi-organ manifestations, such as abdominal/inguinal hernia repair, carpal tunnel surgery, and cardiac valve replacement, should also be considered. Investigational treatment options such as intrathecal ERT are active areas of research, and bone marrow transplantation is in clinical practice. Communication among care providers, social workers, patients and families is essential to inform and guide their decisions, establish realistic expectations, and assess patients' responses.

Streptozotocin-induced diabetes mellitus affects lysosomal enzymes in rat liver

It has been previously shown that dextran sulfate administered to diabetic rats accumulates in the liver and kidney, and this could be due to a malfunction of the lysosomal digestive pathway. The aim of the present study was to evaluate the expression and activities of lysosomal enzymes that act upon proteins and sulfated polysaccharides in the livers of diabetic rats. Diabetes mellitus was induced by streptozotocin in 26 male Wistar rats (12 weeks old), while 26 age-matched controls received only vehicle. The livers were removed on either the 10th or the 30th day of the disease, weighed, and used to evaluate the activity, expression, and localization of lysosomal enzymes. A 50-60% decrease in the specific activities of cysteine proteases, especially cathepsin B, was observed in streptozotocin-induced diabetes mellitus. Expression (mRNA) of cathepsins B and L was also decreased on the 10th, but not on the 30th day. Sulfatase decreased 30% on the 30th day, while glycosidases did not vary (or presented a transitory and slight decrease). There were no apparent changes in liver morphology, and immunohistochemistry revealed the presence of cathepsin B in hepatocyte granules. The decrease in sulfatase could be responsible for the dextran sulfate build-up in the diabetic liver, since the action of sulfatase precedes glycosidases in the digestive pathway of sulfated polysaccharides. Our findings suggest that the decreased activities of cathepsins resulted from decreased expression of their genes, and not from general lysosomal failure, because the levels of glycosidases were normal in the diabetic liver.

Natural history and galsulfase treatment in mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome)--10-year follow-up of patients who previously participated in an MPS VI Survey Study.

Mucopolysaccharidosis VI (MPS VI) is a clinically heterogeneous and progressive disorder with multiorgan manifestations caused by deficient N-acetylgalactosamine-4-sulfatase activity. A cross-sectional Survey Study in individuals (n = 121) affected with MPS VI was conducted between 2001 and 2002 to establish demographics, urinary glycosaminoglycan (GAG) levels, and clinical progression of disease. We conducted a Resurvey Study (ClinicalTrials.gov: NCT01387854) to obtain 10-year follow-up data, including medical histories and clinical assessments (n = 59), and survival status over 12 years (n = 117). Patients received a mean (SD) of 6.8 (2.2) years of galsulfase ERT between baseline (Survey Study) and follow-up. ERT patients increased in height by 20.4 cm in the 4-7-year-old baseline age group and by 16.8 cm in the 8-12-year-old baseline age group. ERT patients <13 years-old demonstrated improvement in forced vital capacity (FVC) by 68% and forced expiratory volume in 1 sec (FEV1) by 55%, and those ≥13 years-old increased FVC by 12.8% and maintained FEV1. Patients with >200 µg/mg baseline uGAG levels increased FVC by 48% in the <13-year-old baseline age group and by 15% in the ≥13-year-old baseline age group. ERT patients who completed the 6-min walk test demonstrated a mean (SD) increase of 65.7 (100.6) m. Cardiac outcomes did not significantly improve or worsen. Observed mortality rate among naïve patients was 50% (7/14) and 16.5% (17/103) in the ERT group (unadjusted hazard ratio, 0.24; 95% CI, 0.10-0.59). Long-term galsulfase ERT was associated with improvements in pulmonary function and endurance, stabilized cardiac function and increased survival.

Mucopolysaccharidosis type II: identification of 30 novel mutations among Latin American patients.

In this study, 103 unrelated South-American patients with mucopolysaccharidosis type II (MPS II) were investigated aiming at the identification of iduronate-2-sulfatase (IDS) disease causing mutations and the possibility of some insights on the genotype-phenotype correlation The strategy used for genotyping involved the identification of the previously reported inversion/disruption of the IDS gene by PCR and screening for other mutations by PCR/SSCP. The exons with altered mobility on SSCP were sequenced, as well as all the exons of patients with no SSCP alteration. By using this strategy, we were able to find the pathogenic mutation in all patients. Alterations such as inversion/disruption and partial/total deletions of the IDS gene were found in 20/103 (19%) patients. Small insertions/deletions/indels (<22 bp) and point mutations were identified in 83/103 (88%) patients, including 30 novel mutations; except for a higher frequency of small duplications in relation to small deletions, the frequencies of major and minor alterations found in our sample are in accordance with those described in the literature.