Airway Findings in Patients with Hunter Syndrome Treated with Intravenous Idursulfase.

People with Hunter syndrome are known to be affected by a variety of airway pathologies. Treatment of Hunter syndrome with the enzyme replacement therapy (ERT) idursulfase is now the standard of care. However, it is not known how ERT changes the progression of airway involvement. To evaluate this, we performed a retrospective analysis of bronchoscopies performed on children with Hunter syndrome who were part of intrathecal ERT trials. Findings for airway pathology were extracted from bronchoscopy reports and analyses were performed for cross-sectional and longitudinal changes in airway disease. One-hundred and thirty bronchoscopies from 23 subjects were analyzed. Upper airway disease (adenoid hypertrophy and/or pharyngomalacia) was reported in 93% and 87% of bronchoscopies, respectively. Laryngeal abnormalities were recognized in 46% of cases. There were lower airway (tracheal and or bronchial) findings in 64% of all bronchoscopies and prevalence increased with age. Evaluations over time adjusted for repeat evaluations showed that increasing airway involvement was associated with older age (p = 0.0007) despite ongoing ERT. No association was discovered between age of intravenous ERT initiation and progression of airway disease. Individuals with Hunter syndrome who are receiving intravenous enzyme replacement therapy showed the progression of airways disease supporting the need for regular airway monitoring and intervention.

Intrathecal idursulfase-IT in patients with neuronopathic mucopolysaccharidosis II: Results from a phase 2/3 randomized study.

Two-thirds of patients with mucopolysaccharidosis II (MPS II; Hunter syndrome) have cognitive impairment. This phase 2/3, randomized, controlled, open-label, multicenter study (NCT02055118) investigated the effects of intrathecally administered idursulfase-IT on cognitive function in patients with MPS II. Children older than 3 years with MPS II and mild-to-moderate cognitive impairment (assessed by Differential Ability Scales-II [DAS-II], General Conceptual Ability [GCA] score) who had tolerated intravenous idursulfase for at least 4 months were randomly assigned (2:1) to monthly idursulfase-IT 10 mg (n = 34) via an intrathecal drug delivery device (IDDD; or by lumbar puncture) or no idursulfase-IT treatment (n = 15) for 52 weeks. All patients continued to receive weekly intravenous idursulfase 0.5 mg/kg as standard of care. Of 49 randomized patients, 47 completed the study (two patients receiving idursulfase-IT discontinued). The primary endpoint (change from baseline in DAS-II GCA score at week 52 in a linear mixed-effects model for repeated measures analysis) was not met: although there was a smaller decrease in DAS-II GCA scores with idursulfase-IT than with no idursulfase-IT at week 52, this was not significant (least-squares mean treatment difference [95% confidence interval], 3.0 [-7.3, 13.3]; p = 0.5669). Changes from baseline in Vineland Adaptive Behavioral Scales-II Adaptive Behavior Composite scores at week 52 (key secondary endpoint) were similar in the idursulfase-IT (n = 31) and no idursulfase-IT (n = 14) groups. There were trends towards a potential positive effect of idursulfase-IT across DAS-II composite, cluster, and subtest scores, notably in patients younger than 6 years at baseline. In a post hoc analysis, there was a significant (p = 0.0174), clinically meaningful difference in change from baseline in DAS-II GCA scores at week 52 with idursulfase-IT (n = 13) versus no idursulfase-IT (n = 6) among those younger than 6 years with missense iduronate-2-sulfatase gene variants. Overall, idursulfase-IT reduced cerebrospinal glycosaminoglycan levels from baseline by 72.0% at week 52. Idursulfase-IT was generally well tolerated. These data suggest potential benefits of idursulfase-IT in the treatment of cognitive impairment in some patients with neuronopathic MPS II. After many years of extensive review and regulatory discussions, the data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

A charitable access program for patients with lysosomal storage disorders in underserved communities worldwide.

BACKGROUND: Lysosomal storage disorders (LSDs) are rare genetic disorders, with heterogeneous clinical manifestations and severity. Treatment options, such as enzyme replacement therapy (ERT), substrate replacement therapy, and pharmacological chaperone therapy, are available for several LSDs, including Gaucher disease (GD), Fabry disease (FD), and Hunter syndrome (mucopolysaccharidosis type II [MPS II]). However, patients in some countries face challenges accessing treatments owing to limited availability of locally licensed, approved drugs. METHODS: The Takeda LSD Charitable access program aims to meet the needs of individuals with GD, FD or MPS II with the greatest overall likelihood of benefit, in selected countries, through donation of ERT to nonprofit organizations, and support for medical capacity-building as well as family support via independent grants. Long-term aims of the program are to establish sustainable healthcare services delivered by local healthcare providers for patients with rare metabolic diseases. Patients receiving treatment through the program are monitored regularly, and their clinical data and progress are reviewed annually by an independent medical expert committee (MEC). The MEC also selects patients for enrollment completely independent from the sponsoring company. RESULTS: As of 31 August, 2019, 199 patients from 13 countries were enrolled in the program; 142 with GD, 41 with MPS II, and 16 with FD. Physicians reported improvements in clinical condition for 147 (95%) of 155 patients with follow-up data at 1 year. CONCLUSIONS: The response rate for follow-up data at 1 year was high, with data collected for > 90% of patients who received ERT through the program showing clinical improvements in the majority of patients. These findings suggest that the program can benefit selected patients previously unable to access disease-specific treatments. Further innovative solutions and efforts are needed to address the challenges and unmet needs of patients with LSDs and other rare diseases around the world.

Improvement in time to treatment, but not time to diagnosis, in patients with mucopolysaccharidosis type I.

OBJECTIVE: Early diagnosis and treatment initiation are important factors for successful treatment of mucopolysaccharidosis type I (MPS I). The purpose of this observational study was to assess whether age at diagnosis and time to first treatment for individuals with MPS I have improved over the last 15 years. STUDY DESIGN: Data from the MPS I Registry (NCT00144794) for individuals with attenuated or severe disease who initiated therapy with laronidase enzyme replacement therapy (ERT) and/or hematopoietic stem cell transplantation (HSCT) between 1 January 2003 and 31 December 2017 were included. RESULTS: Data were available for 740 individuals with attenuated (n=291) or severe (n=424) MPS I (unknown n=25). Median age at diagnosis for attenuated disease did not change over time and ranged between 4.5 and 6 years of age while the median duration from diagnosis to first ERT decreased from 5.6 years before/during 2004 to 2.4 months in 2014-2017. For severe MPS I treated with HSCT, median age at diagnosis was less than 1 year and median time to first treatment was less than 3 months throughout the 15-year observation period. CONCLUSIONS: Times to diagnosis and HSCT initiation for individuals with severe MPS I were consistent over time. For individuals with attenuated MPS I, the time to ERT initiation after diagnosis has improved substantially in the last 15 years, but median age at diagnosis has not improved. Efforts to improve early diagnosis in attenuated MPS I are needed to ensure that patients receive appropriate treatment at the optimal time.

Recommendations for the management of MPS IVA: systematic evidence- and consensus-based guidance.

INTRODUCTION: Mucopolysaccharidosis (MPS) IVA or Morquio A syndrome is an autosomal recessive lysosomal storage disorder (LSD) caused by deficiency of the N-acetylgalactosamine-6-sulfatase (GALNS) enzyme, which impairs lysosomal degradation of keratan sulphate and chondroitin-6-sulphate. The multiple clinical manifestations of MPS IVA present numerous challenges for management and necessitate the need for individualised treatment. Although treatment guidelines are available, the methodology used to develop this guidance has come under increased scrutiny. This programme was conducted to provide evidence-based, expert-agreed recommendations to optimise management of MPS IVA. METHODS: Twenty six international healthcare professionals across multiple disciplines, with expertise in managing MPS IVA, and three patient advocates formed the Steering Committee (SC) and contributed to the development of this guidance. Representatives from six Patient Advocacy Groups (PAGs) were interviewed to gain insights on patient perspectives. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with experience managing patients with MPS IVA and the manuscript was evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers. RESULTS: A total of 87 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) disease-modifying interventions (enzyme replacement therapy [ERT] and haematopoietic stem cell transplantation [HSCT]); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions (including spinal, limb, ophthalmic, cardio-thoracic and ear-nose-throat [ENT] surgeries). Consensus was reached on all statements after two rounds of voting. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance). CONCLUSION: This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS IVA and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

Recommendations for the management of MPS VI: systematic evidence- and consensus-based guidance.

INTRODUCTION: Mucopolysaccharidosis (MPS) VI or Maroteaux-Lamy syndrome (253200) is an autosomal recessive lysosomal storage disorder caused by deficiency in N-acetylgalactosamine-4-sulfatase (arylsulfatase B). The heterogeneity and progressive nature of MPS VI necessitates a multidisciplinary team approach and there is a need for robust guidance to achieve optimal management. This programme was convened to develop evidence-based, expert-agreed recommendations for the general principles of management, routine monitoring requirements and the use of medical and surgical interventions in patients with MPS VI. METHODS: 26 international healthcare professionals from various disciplines, all with expertise in managing MPS VI, and three patient advocates formed the Steering Committee group (SC) and contributed to the development of this guidance. Members from six Patient Advocacy Groups (PAGs) acted as advisors and attended interviews to ensure representation of the patient perspective. A modified-Delphi methodology was used to demonstrate consensus among a wider group of healthcare professionals with expertise and experience managing patients with MPS VI and the manuscript has been evaluated against the validated Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument by three independent reviewers. RESULTS: A total of 93 guidance statements were developed covering five domains: (1) general management principles; (2) recommended routine monitoring and assessments; (3) enzyme replacement therapy (ERT) and hematopoietic stem cell transplantation (HSCT); (4) interventions to support respiratory and sleep disorders; (5) anaesthetics and surgical interventions. Consensus was reached on all statements after two rounds of voting. The greatest challenges faced by patients as relayed by consultation with PAGs were deficits in endurance, dexterity, hearing, vision and respiratory function. The overall guideline AGREE II assessment score obtained for the development of the guidance was 5.3/7 (where 1 represents the lowest quality and 7 represents the highest quality of guidance). CONCLUSION: This manuscript provides evidence- and consensus-based recommendations for the management of patients with MPS VI and is for use by healthcare professionals that manage the holistic care of patients with the intention to improve clinical- and patient-reported outcomes and enhance patient quality of life. It is recognised that the guidance provided represents a point in time and further research is required to address current knowledge and evidence gaps.

The North Carolina Experience with Mucopolysaccharidosis Type I Newborn Screening.

OBJECTIVE: To evaluate the performance of a 2-tiered newborn screening method for mucopolysaccharidosis type I (MPS I) in North Carolina. STUDY DESIGN: The screening algorithm included a flow injection analysis-tandem mass spectrometry assay as a first-tier screening method to measure α-L-iduronidase (IDUA) enzyme activity and Sanger sequencing of the IDUA gene on dried blood spots as a second-tier assay. The screening algorithm was revised to incorporate the Collaborative Laboratory Integrated Reports, an analytical interpretive tool, to reduce the false-positive rate. A medical history, physical examination, IDUA activity, and urinary glycosaminoglycan (GAG) analysis were obtained on all screen-positive infants. RESULTS: A total of 62 734 specimens were screened with 54 screen-positive samples using a cut-off of 15% of daily mean IDUA activity. The implementation of Collaborative Laboratory Integrated Reports reduced the number of specimens that screened positive to 19 infants. Of the infants identified as screen-positive, 1 had elevated urinary GAGs and a homozygous pathogenic variant associated with the severe form of MPS I. All other screen-positive infants had normal urinary GAG analysis; 13 newborns had pseudodeficiency alleles, 3 newborns had variants of unknown significance, and 2 had heterozygous pathogenic variants. CONCLUSIONS: An infant with severe MPS I was identified and referred for a hematopoietic stem cell transplant. Newborn IDUA enzyme deficiency is common in North Carolina, but most are due to pseudodeficiency alleles in infants with normal urinary GAG analysis and no evidence of disease. The pilot study confirmed the need for second-tier testing to reduce the follow-up burden.

Metabonomics reveals altered metabolites related to inflammation and energy utilization at recovery of cystic fibrosis lung exacerbation.

BACKGROUND: Cystic fibrosis lung disease is characterized by chronic bacterial infections in the setting of mucus abnormalities. Patients experience periodic exacerbations that manifest with increased respiratory symptoms that require intensification of therapy with enhanced airway clearance and intravenous (IV) antibiotics. OBJECTIVES: In an observational study we tested if the profile of metabolites in serum distinguished the pre-from post-exacerbation state and which systemically measurable pathways were affected during the process to recovery. METHODS: Serum collected within 48 h of start and completion, respectively of IV antibiotics was collected from people with CF ages 6-30 years. Three day food records were collected prior to each sample. To reduce variation between subjects only subjects who had pancreatic insufficiency, had similar CF mutations, and did not have CF liver disease or diabetes were included. Metabolomic profiling was conducted by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy with metabolites being identified based on retention time/index, mass to charge ratio and comparison to known compounds. Biostatistical analyses used paired t-test with correction for multiple comparisons and orthogonal partial least square discriminant analysis. RESULTS: Thirty subjects (20 male) with a mean ±â€¯SEM age of 15.3 ±â€¯1.2 years participated, 17 of whom had matched food-records. Lung function was significantly improved post-therapy compared to pre-therapy, (mean ±â€¯SEM) 75 ±â€¯4% vs. 68 ±â€¯4% predicted (n = 26). Serum metabonomics showed distinction of the pre-vs. post-therapy groups with 123 compounds contributing to the differentiation pre-versus post-antibiotics by multiple biostatistical analyses. Compounds and pathways affected included bile acids and microbial derived amino acid metabolites, increases in lipid classes of the glycerophospholipid, glycerolipids, cholesterol, phopsholipids, and most pronounced, the class of sphingolipids. Changes in n6/n3 fatty acids, decreased polyamines but increased metabolites in the nitric oxide pathway, and changes in the tryptophan-kynurenine pathway indicated decreased inflammation at resolution of exacerbation. CONCLUSIONS: Changes in serum metabolites that distinguished CF pulmonary exacerbation vs. resolution of symptoms showed evidence of decreased inflammation and improvement from a catabolic state.

Carpal tunnel syndrome in mucopolysaccharidosis I: a registry-based cohort study.

AIM: To characterize carpal tunnel syndrome (CTS) in patients with mucopolysaccharidosis I (MPS I). METHOD: Data were included for patients with MPS I who had either nerve conduction examination that included a diagnosis of CTS or who had CTS release surgery. Although this represented a subset of patients with CTS in the MPS I Registry, the criteria were considered the most objective for data analysis. RESULTS: As of March 2016, 994 patients were categorized with either severe (Hurler syndrome) or attenuated (Hurler-Scheie or Scheie syndromes) MPS I. Among these, 291 had a CTS diagnosis based on abnormal nerve conduction (n=54) or release surgery (n=237). Median ages (minimum, maximum) at first CTS diagnosis were 5 years 2 months (10mo, 16y 2mo) and 9y 11mo (1y 8mo, 44y 1mo) for patients with severe and attenuated MPS I respectively. Most patients had their first CTS diagnosis after MPS I diagnosis (94%) and treatment (hematopoietic stem cell transplant and/or enzyme replacement therapy) (74%). For 11% of patients with attenuated disease, CTS diagnosis preceded MPS I diagnosis by a mean of 7 years 6 months. INTERPRETATION: CTS is a rare complication in pediatric patients and should alert medical care providers to the potential diagnosis of MPS I. Significant delays exist between diagnosis of CTS and MPS I for patients with attenuated disease. WHAT THIS PAPER ADDS: There are significant delays in diagnosing carpal tunnel syndrome (CTS) in patients with mucopolysaccharidosis I (MPS I). Enzyme replacement therapy or hematopoietic stem cell transplant do not prevent the development of CTS. Testing for CTS in patients with MPS I is recommended to prevent irreparable damage. CTS in pediatric patients should alert physicians to potential diagnosis of MPS I.

Homocysteinemia due to MTHFR deficiency in a young adult presenting with bilateral lens subluxations.

The most common cause of isolated inherited homocysteinemia is a deficiency of the enzyme cystathionine ß-synthase (CBS). Clinical manifestations of CBS deficiency can include ectopia lentis, thromboembolism, marfanoid habits, and intellectual disability. CBS deficiency, which affects the transsulfuration pathway, is marked biochemically by elevated serum homocysteine and plasma methionine. We report a patient with homocysteinemia, low plasma methionine, and no significant neurological abnormalities who presented with bilateral subluxated crystalline lenses due to a 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency. MTHFR deficiency, a disorder in the remethylation pathway, can cause mild to severe disease, although most presentations include neurological involvement. MTHFR deficiency has not been previously associated with lens subluxation or complete dislocation. Prolonged exposure to elevated serum homocysteine levels is most likely the explanation for her ectopia lentis. This case expands the differential diagnosis of homocysteinemia and highlights the need for a correct diagnosis to optimize the clinical outcome of patients with this condition.

Inborn Error of Cobalamin Metabolism Associated with the Intracellular Accumulation of Transcobalamin-Bound Cobalamin and Mutations in ZNF143, Which Codes for a Transcriptional Activator.

Vitamin B12 (cobalamin, Cbl) cofactors adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl) are required for the activity of the enzymes methylmalonyl-CoA mutase (MCM) and methionine synthase (MS). Inborn errors of Cbl metabolism are rare Mendelian disorders associated with hematological and neurological manifestations, and elevations of methylmalonic acid and/or homocysteine in the blood and urine. We describe a patient whose fibroblasts had decreased functional activity of MCM and MS and decreased synthesis of AdoCbl and MeCbl (3.4% and 1.0% of cellular Cbl, respectively). The defect in cultured patient fibroblasts complemented those from all known complementation groups. Patient cells accumulated transcobalamin-bound-Cbl, a complex which usually dissociates in the lysosome to release free Cbl. Whole-exome sequencing identified putative disease-causing variants c.851T>G (p.L284*) and c.1019C>T (p.T340I) in transcription factor ZNF143. Proximity biotinylation analysis confirmed the interaction between ZNF143 and HCFC1, a protein that regulates expression of the Cbl trafficking enzyme MMACHC. qRT-PCR analysis revealed low MMACHC expression levels both in patient fibroblasts, and in control fibroblasts incubated with ZNF143 siRNA.

A Cerebrospinal Fluid Collection Study in Pediatric and Adult Patients With Hunter Syndrome

Abstract Hunter syndrome (mucopolysaccharidosis II [MPS II]) is characterized by lysosomal glycosaminoglycan (GAG) accumulation. Although a majority of patients with MPS II experience neurocognitive involvement, few data are available on cerebrospinal fluid (CSF) GAG levels in these patients. This study measured GAG levels in CSF collected from 9 patients with MPS II, including 4 adults (aged ≥18 years) with normal cognition, and 5 children, 3 of them with cognitive impairment. The CSF total GAG levels were generally higher in the 3 patients with cognitive impairment (range 842.9-2360.9 ng/mL) versus those with normal cognitive status (range 356.8-1181.1 ng/mL). Heparan sulfate levels, as measured by mass spectrometry, generally followed a similar pattern, with patients with the severe phenotype having the highest values. These data, limited by small sample size, suggest CSF GAG levels and heparan sulfate levels may be higher in patients with cognitive impairment versus patients with cognitively intact MPS II.

Early initiation of enzyme replacement therapy for the mucopolysaccharidoses.

The mucopolysaccharidoses (MPS), a group of rare genetic disorders caused by defects in glycosaminoglycan (GAG) catabolism, are progressive, multi-systemic diseases with a high burden of morbidity. Enzyme replacement therapy (ERT) is available for MPS I, II, and VI, and may improve walking ability, endurance, and pulmonary function as evidenced by data from pivotal trials and extension studies. Despite these demonstrable benefits, cardiac valve disease, joint disease, and skeletal disease, all of which cause significant morbidity, do not generally improve with ERT if pathological changes are already established. Airway disease improves, but usually does not normalize. These limitations can be well understood by considering the varied functions of GAG in the body. Disruption of GAG catabolism has far-reaching effects due to the triggering of secondary pathogenic cascades. It appears that many of the consequences of these secondary pathogenic events, while they may improve on treatment, cannot be fully corrected even with long-term exposure to enzyme, thereby supporting the treatment of patients with MPS before the onset of clinical disease. This review examines the data from clinical trials and other studies in human patients to explore the limits of ERT as currently used, then discusses the pathophysiology, fetal tissue studies, animal studies, and sibling reports to explore the question of how early to treat an MPS patient with a firm diagnosis. The review is followed by an expert opinion on the rationale for and the benefits of early treatment.

Bronchoscopy and airway management in patients with mucopolysaccharidoses (MPS).

INTRODUCTION: Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders characterized by tissue deposition of glycosaminoglycans (GAG). Their musculoskeletal abnormalities and the GAG storage in the airway result in increased risk for patients undergoing anesthesia. This study evaluates a multi-disciplinary airway management approach and reports upper and lower airway findings of flexible bronchoscopy performed during these procedures. METHODS: This is a retrospective study over 10 years evaluating approaches to and outcomes of airway management and bronchoscopic findings in this patient group. RESULTS: Thirty-one patients underwent a total of 105 anesthetic events of which 74 involved multiple surgical services. The majority of patients were either MPS I (n = 9) or MPS II (n = 19). The median age was 8.6 years (range 1.1-24 years). Airway management by anesthesiologists alone occurred in 31 cases including natural airway (n = 7), perilaryngeal airway (n = 7), oral or nasal intubation (n = 7) or tracheostomy (n = 6) and emergent fiberoptic intubation in four cases. In 74 of the procedures, flexible bronchoscopy was performed which included fiberoptic intubation in 22 cases. Post-operative complications occurred in eight cases mostly when prolonged airway instrumentation had occurred. The most frequent findings on bronchoscopy were GAG deposits/adenoid hypertrophy in 72%, laryngomalacia in 31% and lower airway deposits and/or tracheobronchomalacia in 46% of procedures. Deposits of GAG were seen in patients as young as 4 years of age. CONCLUSION: Our experience demonstrates that a multidisciplinary approach and combined surgeries in MPS provides for safe airway management and allows diagnostic assessments for further patient care without added risks. Significant, multi-factorial airway compromise may occur already in early childhood including upper and lower airway GAG deposits.

Overview of the mucopolysaccharidoses.

The mucopolysaccharidoses (MPSs) are a group of rare, inherited lysosomal storage disorders that are clinically characterized by abnormalities in multiple organ systems and reduced life expectancy. The MPSs are heterogeneous, progressive disorders. Patients typically appear normal at birth, but during early childhood they experience the onset of clinical disease, including skeletal, joint, airway and cardiac involvement, hearing and vision impairment, and mental retardation in the severe forms of MPS I, MPS II and MPS VII and all subtypes of MPS III. There are two treatment options for patients with MPS that are directed at the underlying pathophysiology: haematopoietic stem cell transplantation, which is useful for selected patients, and recombinant i.v. enzyme replacement therapy, which is available for MPS I, II and VI. Early diagnosis and treatment can improve patient outcomes and may reduce the disease burden on patients and caregivers. As skeletal and joint abnormalities are characteristic of many patients with MPS, rheumatologists are positioned to recognize the features of the disease and to facilitate early diagnosis and referral. In this overview, the clinical features of the MPS disorders and a brief review of treatment options will be presented in order to aid the rheumatologist in recognizing the features of these rare genetic disorders.

Restoration of central nervous system alpha-N-acetylglucosaminidase activity and therapeutic benefits in mucopolysaccharidosis IIIB mice by a single intracisternal recombinant adeno-associated viral type 2 vector delivery.

BACKGROUND: Finding efficient central nervous system (CNS) delivery approaches has been the major challenge facing therapeutic development for treating diseases with global neurological manifestation, such as mucopolysaccharidosis (MPS) IIIB, a lysosomal storage disease, caused by autosomal recessive defect of alpha-N-acetylglucosaminidase (NaGlu). Previously, we developed an approach, intracisternal (i.c.) injection, to deliver recombinant adeno-associated viral (rAAV) vector to the CNS of mice, leading to a widespread periventricular distribution of transduction. METHODS: In the present study, we delivered rAAV2 vector expressing human NaGlu into the CNS of MPS IIIB mice by an i.c. injection approach, to test its therapeutic efficacy and feasibility for treating the neurological manifestation of the disease. RESULTS: We demonstrated significant functional neurological benefits of a single i.c. vector infusion in adult MPS IIIB mice. The treatment slowed the disease progression by mediating widespread recombinant NaGlu expression in the CNS, resulting in the reduction of brain lysosomal storage pathology, significantly improved cognitive function and prolonged survival. However, persisting motor function deficits suggested that pathology in areas outside the CNS contributes to the MPS IIIB behavioral phenotype. The therapeutic benefit of i.c. rAAV2 delivery was dose-dependent and could be attribute solely to the CNS transduction because the procedure did not lead to detectable transduction in somatic tissues. CONCLUSIONS: A single IC rAAV2 gene delivery is functionally beneficial for treating the CNS disease of MPS IIIB in mice. It is immediately clinically translatable, with the potential of improving the quality of life for patients with MPS IIIB.

Evaluation of disease severity in mucopolysaccharidoses.

The mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders characterized by a wide variation in symptoms and progression rates. Each of the MPS types is caused by a deficiency in one of the enzymes involved in the catabolic pathway of glycosaminoglycans. MPS are usually suspected on the basis of the concomitant presence of several typical features of the disease, such as short stature, coarse facial features, loss of hearing, bone deformities, joint stiffness, organomegaly, respiratory and cardiovascular complications, and, in some cases, developmental delay. Very reduced or absent enzyme activity is required to confirm an MPS diagnosis. In the past, treatment of MPS was limited to the management of individual symptoms of the diseases. Currently, specific therapies such as hematopoietic stem cell transplantation and enzyme replacement therapy have improved the outlook for many MPS patients. To monitor disease progression and the impact of therapy in these patients, there is need for a validated scoring system for evaluating disease severity in MPS. A scoring system should take into account all aspects of MPS, particularly quality of life and functioning of arms, hands and legs and related mobility, endurance, self care and social functioning. This paper discusses several of the available scoring systems for bone/skeletal disorders and their potential usefulness in patients with MPS.

Multidisciplinary management of Hunter syndrome.

Hunter syndrome is a rare, X-linked disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase. In the absence of sufficient enzyme activity, glycosaminoglycans accumulate in the lysosomes of many tissues and organs and contribute to the multisystem, progressive pathologies seen in Hunter syndrome. The nervous, cardiovascular, respiratory, and musculoskeletal systems can be involved in individuals with Hunter syndrome. Although the management of some clinical problems associated with the disease may seem routine, the management is typically complex and requires the physician to be aware of the special issues surrounding the patient with Hunter syndrome, and a multidisciplinary approach should be taken. Subspecialties such as otorhinolaryngology, neurosurgery, orthopedics, cardiology, anesthesiology, pulmonology, and neurodevelopment will all have a role in management, as will specialty areas such as physiotherapy, audiology, and others. The important management topics are discussed in this review, and the use of enzyme-replacement therapy with recombinant human iduronate-2-sulfatase as a specific treatment for Hunter syndrome is presented.

Mucopolysaccharidosis I: management and treatment guidelines.

OBJECTIVE: Disease management for mucopolysaccharidosis type I has been inconsistent because of disease rarity (approximately 1 case per 100,000 live births), phenotypic heterogeneity, and limited therapeutic options. The availability of hematopoietic stem cell transplantation and the recent introduction of enzyme replacement therapy for mucopolysaccharidosis I necessitate the establishment of system-specific management guidelines for this condition. METHODS: Twelve international experts on mucopolysaccharidosis I met in January 2003 to draft management and treatment guidelines for mucopolysaccharidosis I. Initial guidelines were revised and updated in 2008, on the basis of additional clinical data and therapeutic advances. Recommendations are based on our extensive clinical experience and a review of the literature. RESULTS: All patients with mucopolysaccharidosis I should receive a comprehensive baseline evaluation, including neurologic, ophthalmologic, auditory, cardiac, respiratory, gastrointestinal, and musculoskeletal assessments, and should be monitored every 6 to 12 months with individualized specialty assessments, to monitor disease progression and effects of intervention. Patients are best treated by a multidisciplinary team. Treatments consist of palliative/supportive care, hematopoietic stem cell transplantation, and enzyme replacement therapy. The patient's age (>2 years or < or =2 years), predicted phenotype, and developmental quotient help define the risk/benefit profile for hematopoietic stem cell transplantation (higher risk but can preserve central nervous system function) versus enzyme replacement therapy (low risk but cannot cross the blood-brain barrier). CONCLUSION: We anticipate that provision of a standard of care for the treatment of patients with mucopolysaccharidosis I will optimize clinical outcomes and patients' quality of life.

The MPS I registry: design, methodology, and early findings of a global disease registry for monitoring patients with Mucopolysaccharidosis Type I.

A global, observational disease registry has been established to characterize the course of disease and track clinical outcomes in patients with Mucopolysaccharidosis Type I (MPS I), a rare and treatable lysosomal storage disorder. This report outlines procedures for data collection and presents the recommended minimum schedule of assessments that comprise the disease-specific clinical and laboratory parameters that are tracked in the database. Aggregate data are summarized for the first 302 patients enrolled, representing entries from 24 countries. The median current age of the patients is 9.0 years (range: 0.4-64.8). Syndrome diagnoses include 47% Hurler (severe form), 25% Hurler-Scheie (attenuated form with an intermediate phenotype), 13% Scheie (most attenuated form), and 15% unknown. Younger ages at symptom onset and disease diagnosis are associated with the severe Hurler syndrome, but there is overlap among syndromes. Diagnosis was delayed by years to decades in several patients with Hurler-Scheie and Scheie syndromes. Patients with symptom onset before age 5 are more likely to have a gibbus, cognitive impairment, and pneumonia, whereas patients with symptom onset above age 5 are more likely to have carpal tunnel syndrome, myelopathy, and glaucoma. Cardiac valve abnormalities, joint contractures, corneal clouding, and hernia are reported by over 70% of patients regardless of the age of symptom onset. Approximately 80% of the patients have received enzyme replacement therapy, hematopoietic stem cell transplantation, or both. Overall, the MPS I Registry database contains a broad sample of the global patient population, providing a potentially useful tool for expanding knowledge of MPS I and facilitating evidence-based decisions about the optimal means of monitoring and treating affected individuals.