Identification and characterization of novel genetic variants in the first Chinese family of mucopolysaccharidosis IIIC (Sanfilippo C syndrome).

Mucopolysaccharidosis type IIIC (MPS IIIC) is one of inherited lysosomal storage disorders, caused by deficiencies in lysosomal hydrolases degrading acidic mucopolysaccharides. The gene responsible for MPS IIIC is HGSNAT, which encodes an enzyme that catalyses the acetylation of the terminal glucosamine residues of heparan sulfate. So far, few studies have focused on the genetic landscape of MPS IIIC in China, where IIIA and IIIB were the major subtypes. In this study, we utilized whole-exome sequencing (WES) to identify novel compound heterozygous variants in the HGSNAT gene from a Chinese patient with typical MPS IIIC symptoms: c.743G>A; p.Gly248Glu and c.1030C>T; p.Arg344Cys. We performed in silico analysis and experimental validation, which confirmed the deleterious pathogenic nature of both variants, as evidenced by the loss of HGSNAT activity and failure of lysosomal localization. To the best of our knowledge, the MPS IIIC is first confirmed by clinical, biochemical and molecular genetic findings in China. Our study thus expands the spectrum of MPS IIIC pathogenic variants, which is of importance to dissect the pathogenesis and to carry out clinical diagnosis of MPS IIIC. Moreover, this study helps to depict the natural history of Chinese MPS IIIC populations.

Clinical investigator perspectives on patient outcomes in children with neuronopathic mucopolysaccharidosis II during intrathecal idursulfase-IT treatment.

BACKGROUND: Mucopolysaccharidosis II (MPS II) is a rare lysosomal storage disease characterized by iduronate-2-sulfatase gene (IDS) deficiency and downstream glycosaminoglycan accumulation. Two-thirds of patients present with neuronopathic disease and evaluating cognitive function in these patients is challenging owing to limitations of currently available tests. During the clinical development of intrathecal idursulfase (idursulfase-IT), regulatory authorities requested qualitative data to further understand the neurocognitive changes observed by the investigators through the clinical trials. RESULTS: This qualitative study consisted of semi-structured interviews with all nine of the principal investigators who participated in the idursulfase-IT phase 2/3 (NCT02055118) and extension (NCT02412787) trials. These investigators enrolled the 56 patients with neuronopathic MPS II who qualified for the extension phase of the trial. The investigators were asked to rate the disease status of their patients. Of the 56 patients, 49 (88%) were rated as having disease that was improved/improving, stabilized or slowing progression compared with the expected outcomes with no treatment. Three patients were rated as worsening, while the remaining four patients were considered to have slowing progression or worsening disease. Similar results were demonstrated for patients aged from 3 to under 6 years at baseline, with 33 of 39 patients (85%) rated as having disease that was improved/improving, stabilized or slowing progression. Of the seven patients rated with slowing progression/worsening or worsening disease, five of them had an IDS variant other than missense, while two had a missense class variant. All the assigned improved/improving ratings were in patients receiving idursulfase-IT from the start of the phase 2/3 trial. Moreover, patients under 3 years of age at baseline were all rated as either improved/improving or stabilized disease. In a blinded review of patient profiles, investigators were requested to assign a disease status rating to 18 patients with large IDS deletions; 67% of these patients were rated as improved/improving or stabilized disease. CONCLUSIONS: This qualitative analysis provides a snapshot of clinicians' considerations when evaluating treatment in patients with neuronopathic MPS II, compared with the expected decline in cognitive function in the absence of treatment. The results highlight the importance of robust assessment tools in treatment evaluation.

Airway and Anaesthetic Management of Adult Patients with Mucopolysaccharidoses Undergoing Cardiac Surgery.

Background: Mucopolysaccharidoses (MPSs) are rare congenital lysosomal storage disorders due to a deficiency of enzymes metabolising glycosaminoglycans, leading to their accumulation in tissues. This multisystem disease often requires surgical intervention, including valvular cardiac surgery. Adult MPSs have complex airways making anaesthesia risky. Methods: We report novel three-dimensional (3D) modelling airway assessments and multidisciplinary peri-operative airway management. Results: Five MPS adults underwent cardiac surgery at the national MPS cardiac centre (type I = 4, type II = 1; ages 20, 24, 33, 35, 37 years; two males, three females). All had complex airway abnormalities. Assessments involved examination, nasendoscopy, imaging, functional studies, 3D reconstruction, virtual endoscopy, virtual reality and simulation using computerised, physical modelling. Awake oral fibre-optic intubation was achieved via airway conduit. Staged extubation was performed on the first post-operative day under laryngo-tracheoscopic guidance. The post-operative period involved chest physiotherapy and occupational therapy. All patients had safe intubation, ventilation and extubation. Four had good cardiac surgical outcomes, one (MPS type I; age 35 years) was inoperable due to endocarditis. None had post-operative airway complications. Conclusions: Expertise from cardiovascular-heart team, multidisciplinary airway management, use of novel techniques is vital. Traditional airway assessments are insufficient, so ENT input, radiology and computerised methods to assess and simulate the airway in 3D by collaboration with clinical engineering is essential.

Characterization of early markers of disease in the mouse model of mucopolysaccharidosis IIIB.

BACKGROUND: Mucopolysaccharidosis (MPS) IIIB, also known as Sanfilippo Syndrome B, is a devastating childhood disease. Unfortunately, there are currently no available treatments for MPS IIIB patients. Yet, animal models of lysosomal storage diseases have been valuable tools in identifying promising avenues of treatment. Enzyme replacement therapy, gene therapy, and bone marrow transplant have all shown efficacy in the MPS IIIB model systems. A ubiquitous finding across rodent models of lysosomal storage diseases is that the best treatment outcomes resulted from intervention prior to symptom onset. Therefore, the aim of the current study was to identify early markers of disease in the MPS IIIB mouse model as well as examine clinically-relevant behavioral domains not yet explored in this model. METHODS: Using the MPS IIIB mouse model, we explored early developmental trajectories of communication and gait, and later social behavior, fear-related startle and conditioning, and visual capabilities. In addition, we examined brain structure and function via magnetic resonance imaging and diffusion tensor imaging. RESULTS: We observed reduced maternal isolation-induced ultrasonic vocalizations in MPS IIIB mice relative to controls, as well as disruption in a number of the spectrotemporal features. MPS IIIB also exhibited disrupted thermoregulation during the first two postnatal weeks without any differences in body weight. The developmental trajectories of gait were largely normal. In early adulthood, we observed intact visual acuity and sociability yet a more submissive phenotype, increased aggressive behavior, and decreased social sniffing relative to controls. MPS IIIB mice showed greater inhibition of startle in response to a pretone with a decrease in overall startle response and reduced cued fear memory. MPS IIIB also weighed significantly more than controls throughout adulthood and showed larger whole brain volumes and normalized regional volumes with intact tissue integrity as measured with magnetic resonance and diffusion tensor imaging, respectively. CONCLUSIONS: Together, these results indicate disease markers are present as early as the first two weeks postnatal in this model. Further, this model recapitulates social, sensory and fear-related clinical features. Our study using a mouse model of MPS IIIB provides essential baseline information that will be useful in future evaluations of potential treatments.

Further characterization of ARSK-related mucopolysaccharidosis type 10.

Mucopolysaccharidosis type 10 is caused by biallelic variants in ARSK, which encodes for a lysosomal sulfatase. To date, seven patients with a mild phenotype resembling spondyloepiphyseal dysplasia or multiple epiphyseal dysplasia have been described. In this report, we present two novel ARSK variants and report clinical and radiological findings of three patients. The patients' initial complaints were hip or knee pain and a waddling gait. All patients showed normal intelligence, normal hearing and eye examinations, and none had organomegaly. While typical dysostosis multiplex findings were not observed, mild platyspondyly with anterior beaking of some vertebral bodies, irregular vertebral endplates, wide ribs, inferior tapering of the ilea with a poorly developed acetabulum, irregularity of the central part of the femoral head, delayed ossification of the carpals were noted. Remarkably, all patients showed metaphyseal striation of the long bones, a crucial diagnostic clue to identify ARSK-related MPS type 10. Interestingly, vertebral involvement regressed during follow-up. On the other hand, hip dysplasia progressed in all patients. In conclusion, this study provides valuable long-term results on a recently discovered form of MPS.

Disturbances in mitochondrial bioenergetics and control quality and unbalanced redox homeostasis in the liver of a mouse model of mucopolysaccharidosis type II.

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is a lysosomal storage disease caused by mutations in the gene encoding the enzyme iduronate 2-sulfatase (IDS) and biochemically characterized by the accumulation of glycosaminoglycans (GAGs) in different tissues. It is a multisystemic disorder that presents liver abnormalities, the pathophysiology of which is not yet established. In the present study, we evaluated bioenergetics, redox homeostasis, and mitochondrial dynamics in the liver of 6-month-old MPS II mice (IDS-). Our findings show a decrease in the activity of α-ketoglutarate dehydrogenase and an increase in the activities of succinate dehydrogenase and malate dehydrogenase. The activity of mitochondrial complex I was also increased whereas the other complex activities were not affected. In contrast, mitochondrial respiration, membrane potential, ATP production, and calcium retention capacity were not altered. Furthermore, malondialdehyde levels and 2',7'-dichlorofluorescein oxidation were increased in the liver of MPS II mice, indicating lipid peroxidation and increased ROS levels, respectively. Sulfhydryl and reduced glutathione levels, as well as glutathione S-transferase, glutathione peroxidase (GPx), superoxide dismutase, and catalase activities were also increased. Finally, the levels of proteins involved in mitochondrial mass and dynamics were decreased in knockout mice liver. Taken together, these data suggest that alterations in energy metabolism, redox homeostasis, and mitochondrial dynamics can be involved in the pathophysiology of liver abnormalities observed in MPS II.

Morquio B disease: a case report.

Mucopolysaccharidosis IV type B, or Morquio B disease (MBD), is an autosomal recessive disorder caused by a genetic mutation in GLB1 gene encoding for ß-galactosidase on chromosome 3p22.33. ß-galactosidase deficiency can result in two different conditions, GM1 gangliosidosis and MBD, of which MBD has a milder phenotype and presents later in life with keratan sulfate accumulation in the retina and cartilage. In this case report, we present a patient diagnosed with MBD at the age of 5 after initially presenting with Morquio dysostosis multiplex and characteristic radiographic findings. Genetic testing confirmed that the patient has ß-galactosidase deficiency due to mutation W273l/N484K on GLB1 gene. The patient exhibited elevated mucopolysaccharide levels in urine at 18 mg/mmol and demonstrated an abnormal band pattern of urine oligosaccharides on electrophoresis. The activity of ß-galactosidase in his white blood cells was reduced to 12.3 nmol/h/mg protein. At the time of diagnosis, the patient did not present with gait and ambulation issues, but his ability to walk progressively deteriorated in his adolescence as a result of instability and pain in the ankle, knee, and hip joints, accompanied by a global decrease in muscle strength. This case report is the first in the literature to provide an in-depth exploration of the orthopedic treatment and follow-up received by a young adolescent with MBD to provide symptom relief and improve walking ability.

Cellular Organelle-Related Transcriptomic Profile Abnormalities in Neuronopathic Types of Mucopolysaccharidosis: A Comparison with Other Neurodegenerative Diseases.

Mucopolysaccharidoses (MPS) are a group of diseases caused by mutations in genes encoding lysosomal enzymes that catalyze reactions of glycosaminoglycan (GAG) degradation. As a result, GAGs accumulate in lysosomes, impairing the proper functioning of entire cells and tissues. There are 14 types/subtypes of MPS, which are differentiated by the kind(s) of accumulated GAG(s) and the type of a non-functional lysosomal enzyme. Some of these types (severe forms of MPS types I and II, MPS III, and MPS VII) are characterized by extensive central nervous system disorders. The aim of this work was to identify, using transcriptomic methods, organelle-related genes whose expression levels are changed in neuronopathic types of MPS compared to healthy cells while remaining unchanged in non-neuronopathic types of MPS. The study was conducted with fibroblast lines derived from patients with neuronopathic and non-neuronopathic types of MPS and control (healthy) fibroblasts. Transcriptomic analysis has identified genes related to cellular organelles whose expression is altered. Then, using fluorescence and electron microscopy, we assessed the morphology of selected structures. Our analyses indicated that the genes whose expression is affected in neuronopathic MPS are often associated with the structures or functions of the cell nucleus, endoplasmic reticulum, or Golgi apparatus. Electron microscopic studies confirmed disruptions in the structures of these organelles. Special attention was paid to up-regulated genes, such as PDIA3 and MFGE8, and down-regulated genes, such as ARL6IP6, ABHD5, PDE4DIP, YIPF5, and CLDN11. Of particular interest is also the GM130 (GOLGA2) gene, which encodes golgin A2, which revealed an increased expression in neuronopathic MPS types. We propose to consider the levels of mRNAs of these genes as candidates for biomarkers of neurodegeneration in MPS. These genes may also become potential targets for therapies under development for neurological disorders associated with MPS and candidates for markers of the effectiveness of these therapies. Although fibroblasts rather than nerve cells were used in this study, it is worth noting that potential genetic markers characteristic solely of neurons would be impractical in testing patients, contrary to somatic cells that can be relatively easily obtained from assessed persons.

Hand Radiographs in Skeletal Dysplasia: A Pictorial Review.

Skeletal dysplasias or osteochondrodysplasias comprise a large heterogeneous group of genetic disorders and possess significant overlap on imaging, which adds to the dilemma of the reporting radiologist. These entities are routinely evaluated with a detailed skeletal survey and hand radiographs form a crucial part of a complete survey. Certain conditions have characteristic imaging findings that enable a diagnosis be made on hand radiograph alone. Additionally, hand radiographs may also demonstrate findings that may be suggestive of a particular diagnosis/differential diagnoses and would warrant further assessment for proving the same. We aim to demonstrate the use of hand radiographs in diagnosis of various such entities through this review. Although they cannot replace a complete skeletal survey in the diagnosis, hand radiographs performed for other indications might alert a radiologist to the diagnosis of an unsuspected skeletal dysplasia.

Morquio A Syndrome: Identification of Differential Patterns of Molecular Pathway Interactions in Bone Lesions.

Mucopolysaccharidosis type IVA (MPS IVA; Morquio A syndrome) is a rare autosomal recessive lysosomal storage disease (LSD) caused by deficiency of a hydrolase enzyme, N-acetylgalactosamine-6-sulfate sulfatase, and characterized clinically by mainly musculoskeletal manifestations. The mechanisms underlying bone involvement in humans are typically explored using invasive techniques such as bone biopsy, which complicates analysis in humans. We compared bone proteomes using DDA and SWATH-MS in wild-type and MPS IVA knockout mice (UNT) to obtain mechanistic information about the disease. Our findings reveal over 1000 dysregulated proteins in knockout mice, including those implicated in oxidative phosphorylation, oxidative stress (reactive oxygen species), DNA damage, and iron transport, and suggest that lactate dehydrogenase may constitute a useful prognostic and follow-up biomarker. Identifying biomarkers that reflect MPS IVA clinical course, severity, and progression have important implications for disease management.

Modeling Lysosomal Storage Disorders in an Innovative Way: Establishment and Characterization of Stem Cell Lines from Human Exfoliated Deciduous Teeth of Mucopolysaccharidosis Type II Patients.

Among the many lysosomal storage disorders (LSDs) that would benefit from the establishment of novel cell models, either patient-derived or genetically engineered, is mucopolysaccharidosis type II (MPS II). Here, we present our results on the establishment and characterization of two MPS II patient-derived stem cell line(s) from deciduous baby teeth. To the best of our knowledge, this is the first time a stem cell population has been isolated from LSD patient samples obtained from the dental pulp. Taking into account our results on the molecular and biochemical characterization of those cells and the fact that they exhibit visible and measurable disease phenotypes, we consider these cells may qualify as a valuable disease model, which may be useful for both pathophysiological assessments and in vitro screenings. Ultimately, we believe that patient-derived dental pulp stem cells (DPSCs), particularly those isolated from human exfoliated deciduous teeth (SHEDs), may represent a feasible alternative to induced pluripotent stem cells (iPSCs) in many labs with standard cell culture conditions and limited (human and economic) resources.

Analysis of caregiver perspectives on patients with mucopolysaccharidosis II treated with pabinafusp alfa: results of qualitative interviews in Japan.

BACKGROUND: Mucopolysaccharidosis type II (MPS II), or Hunter syndrome, is a rare X-linked metabolic disorder predominantly affecting males. Pabinafusp alfa, an iduronate-2-sulfatase enzyme designed to cross the blood-brain barrier, was approved in Japan in 2021 as the first enzyme replacement therapy targeting both the neuropathic and somatic signs and symptoms of MPS II. This study reports caregivers' experiences of MPS II patients receiving pabinafusp alfa through qualitative interviews. METHODS: Semi-structured, qualitative interviews were conducted with caregivers at seven clinical sites in Japan using a semi-structured moderation guide (Voice of the Caregiver guide). Thematic analysis was applied to the interview transcripts to identify symptoms and health-related quality of life impacts at baseline, changes during treatment, and overall treatment experience. RESULTS: Seven caregivers from 16 trial sites participated, representing seven children aged 8-18 years who had received pabinafusp alfa for 3.3-3.5 years at the time of the interviews. Data suggest a general trend toward improvement in multiple aspects, although not all caregivers observed discernible changes. Reported cognitive improvements included language skills, concentration, self-control, eye contact, mental clarity, concept understanding, following instructions, and expressing personal needs. Further changes were reported that included musculoskeletal improvements and such somatic changes as motor function, mobility, organ involvement, joint mobility, sleep patterns, and fatigue. Four caregivers reported improvements in family quality of life, five expressed treatment satisfaction, and all seven indicated a strong willingness to continue treatment of their children with pabinafusp alfa. CONCLUSION: Caregivers' perspectives in this study demonstrate treatment satisfaction and improvement in various aspects of quality of life following therapy with pabinafusp alfa. These findings enhance understanding of pabinafusp alfa's potential benefits in treating MPS II and contribute to defining MPS II-specific outcome measures for future clinical trials.

Identification of new variants in patients with mucopolysaccharidosis in consanguineous Iranian families.

Introduction: Mucopolysaccharidoses are a group of lysosomal storage disorders that include seven types that are classified based on the enzymes that are disrupted. Malfunction of these enzymes leads to the accumulation of glycosaminoglycans (GAGs) in various tissues. Due to genetic and clinical heterogeneity, diagnosing and distinguishing the different types is challenging. Genetic methods such as whole exome sequencing (WES) and Sanger sequencing are accurate methods for detecting pathogenic variants in patients. Methods: Thirty-two cases of mucopolysaccharidosis, predominantly from families with consanguineous marriages, were genetically examined. Out of these, fourteen cases underwent targeted sequencing, while the rest underwent WES. The results of WES were analyzed and the pathogenicity of the variants was examined using bioinformatics tools. In addition, a segregation analysis within families was carried out. Results: In most cases, a pathogenic or likely pathogenic variant was detected. Sixteen previously reported variants and six new variants were detected in the known IDS (c.458G>C, c.701del, c.920T>G), GNS (c.1430A>T), GALNS (c.1218_1221dup), and SGSH (c.149T>C) genes. Furthermore, we discovered a c.259G>C substitution in the NAGLU gene for the first time in three homozygous patients. This substitution was previously reported as heterozygous. Except for the variants related to the IDS gene, which were hemizygous, all the other variants were homozygous. Discussion: It appears that the high rate of consanguineous marriages in the families being studied has had a significant impact on the occurrence of this disease. Overall, these findings could expand the spectrum of pathogenic variants in mucopolysaccharidoses. Genetic methods, especially WES, are very accurate and can be used alone or in conjunction with other diagnostic methods for a more precise and rapid diagnosis of mucopolysaccharidoses. Additionally, they could be beneficial for family screening and disease prevention.

Evaluation, in a highly specialised enzyme laboratory, of a digital microfluidics platform for rapid assessment of lysosomal enzyme activity in dried blood spots.

Lysosomal storage disorders (LSDs) are predominantly enzyme deficiencies leading to substrate accumulation, causing progressive damage to multiple organs. To date, a crucial part of diagnosing LSDs is measuring enzymatic activity in leucocytes, plasma, or dried blood spots (DBS). Here, we present results from a proof-of-principle study, evaluating an innovative digital microfluidics (DMF) platform, referred to as SEEKER®, that can measure the activity of the following four lysosomal enzymes from DBS: α-L-iduronidase (IDUA) for mucopolysaccharidosis I (MPS I), acid α-glucosidase (GAA) for Pompe disease, ß-glucosidase (GBA) for Gaucher disease, and α-galactosidase A (GLA) for Fabry disease. Over 900 DBS were analysed from newborns, children, and adults. DMF successfully detected known patients with MPS I, Pompe disease, and Gaucher disease, and known males with Fabry disease. This is the first demonstration of this multiplexed DMF platform for identification of patients with LSDs in a specialised diagnostic enzyme laboratory environment. We conclude that this DMF platform is relatively simple, high-throughput, and could be readily accommodated into a specialised laboratory as a first-tier test for MPS I, Pompe disease, and Gaucher disease for all patients, and Fabry disease for male patients only.

Specific GAG ratios in the diagnosis of mucopolysaccharidoses.

Mucopolysaccharidoses (MPS) screening is tedious and still performed by analysis of total glycosaminoglycans (GAG) using 1,9-dimethylmethylene blue (DMB) photometric assay, although false positive and negative tests have been reported. Analysis of differentiated GAGs have been pursued classically by gel electrophoresis or more recently by quantitative LC-MS assays. Secondary elevations of GAGs have been reported in urinary tract infections (UTI). In this manuscript, we describe the diagnostic accuracy of urinary GAG measurements by LC-MS for MPS typing in 68 untreated MPS and mucolipidosis (ML) patients, 183 controls and 153 UTI samples. We report age-dependent reference values and cut-offs for chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS) and keratan sulfate (KS) and specific GAG ratios. The use of HS/DS ratio in combination to GAG concentrations normalized to creatinine improves the diagnostic accuracy in MPS type I, II, VI and VII. In total 15 samples classified to the wrong MPS type could be correctly assigned using HS/DS ratio. Increased KS/HS ratio in addition to increased KS improves discrimination of MPS type IV by excluding false positives. Some samples of UTI patients showed elevation of specific GAGs, mainly CS, KS and KS/HS ratio and could be misclassified as MPS type IV. Finally, DMB photometric assay performed in MPS and ML samples reveal four false negative tests (sensitivity of 94%). In conclusion, specific GAG ratios in complement to quantitative GAG values obtained by LC-MS enhance discrimination of MPS types. Exclusion of patients with UTI improve diagnostic accuracy in MPS IV but not in other types.

A novel graphene oxide-based fluorescence method for detection of urine glycosaminoglycans.

Glycosaminoglycans (GAGs) serve as a biomarker for mucopolysaccharidoses disease. In this study, a novel fluorometric method was developed to measure total GAGs in urine. Graphene oxide (GO) and rhodamine B (RhB), a cationic fluorescent dye, were employed in the development of the method. RhB attaches to the GO surface via electrostatic attraction, leading to the quenching of its fluorescence upon the establishment of the RhB-GO complex. However, the presence of GAGs prompts a resurgence of intense fluorescence. The linear range of the method is between 5.00 and 70.00 mg/L. The total GAG levels of urine samples analyzed using the method agree with the results of the biochemistry analysis laboratory (65.85 and 79.18 mg/L; 73.30 ± 1.76 and 72.21 ± 2.21). The method is simple, accurate, and sensitive and may be used for both first-step diagnosis of the mucopolysaccharidoses and detection of individual GAGs for studies of GAG-related research and other biological applications.

Caregiver experiences and observations of intrathecal idursulfase-IT treatment in a phase 2/3 trial in pediatric patients with neuronopathic mucopolysaccharidosis II.

BACKGROUND: Approximately two-thirds of patients with mucopolysaccharidosis II (MPS II) have a severe, neuronopathic phenotype, characterized by somatic, cognitive, and behavioral issues. Current standard of care for the treatment of MPS II is enzyme replacement therapy with intravenous recombinant human iduronate-2-sulfatase (idursulfase). To target cognitive manifestations of MPS II, idursulfase has been formulated for intrathecal administration into the cerebrospinal fluid (idursulfase-IT). In accordance with recommendations for patient-focused drug development, semi-structured interviews were conducted to assess caregiver experiences and observations in a 52-week phase 2/3 trial of idursulfase-IT, in addition to intravenous idursulfase in pediatric patients with neuronopathic MPS II, or a substudy which enrolled patients younger than 3 years old, all of whom received idursulfase-IT. RESULTS: Overall, 46 caregivers providing care for 50 children (mean [range] age 7.9 [3-17] years at interview) took part in a single 60-min exit interview; six of these children had participated in the substudy. Qualitative and quantitative data were obtained demonstrating the burden of MPS II experienced by caregivers and their families. Following participation in the trials, 39 (78%) of the children were reported by their caregivers to have experienced improvements in the symptoms and impact of disease. Of those with improvements, 37 (95%) experienced cognitive improvements and 26 (67%) experienced emotional/behavioral improvements. Overall, 43 children (86%) were rated by caregivers as having moderate or severe symptoms before the trials; after the trials, 28 children (56%) were considered to have mild or no symptoms. For the six children who participated in the substudy, these proportions were 83% and 100%, respectively. Caregivers' qualitative descriptions of trial experiences suggested improvements in children's verbal and non-verbal functioning and spatial and motor skills, as well as a positive impact on family life. CONCLUSIONS: This study revealed caregiver-reported improvements in children's MPS II symptoms and the impact of the disease on patients and their families. There was a trend for cognitive improvement and a reduction in severity of MPS II symptoms. After many years of extensive review and regulatory discussions of idursulfase-IT, the clinical trial data were found to be insufficient to meet the evidentiary standard to support regulatory filings.

Historia natural de la mucopolisacaridosis III en una serie de pacientes colombianos / Natural history of mucopolysaccharidosis type III in a series of Colombian patients

Introducción: La mucopolisacaridosis de tipo III (MPS III), o síndrome de Sanfilippo, es un trastorno de almacenamiento lisosómico con características neurodegenerativas progresivas, predominante del sistema nervioso central. Su diagnóstico se basa en el cuadro clínico, y priman alteraciones en el neurodesarrollo y neuropsiquiátricas, incluso antes de la presencia de alteraciones fenotípicas. El análisis bioquímico para identificar el tipo de glucosaminoglucanos presente, la determinación enzimática y el estudio de genética molecular confirman la enfermedad. Casos clínicos: Se realiza la descripción clínica de ocho pacientes con diagnóstico de MPS III en Colombia, con síntomas iniciales en relación con retraso del desarrollo y trastornos comportamentales evidenciados entre los 3 y 8 años, asociado a facies toscas, cejas pobladas, hepatomegalia y pérdida auditiva progresiva en todos los casos. Uno de los pacientes presentó anomalías cardíacas; dos de ellos, epilepsia focal; y en uno se evidenció atrofia óptica. Todos presentaron alteraciones en las neuroimágenes con evidencia de pérdida del volumen parenquimatoso, atrofia del cuerpo calloso y adelgazamiento cortical; el diagnostico se realizó a través de estudios bioquímicos de cromatografía de glucosaminoglucanos y todos cuentan con un estudio genético confirmatorio. Conclusiones: La MPS III es un desafío diagnóstico, particularmente en pacientes con un curso atenuado de la enfermedad, debido al curso variable, síntomas neuropsiquiátricos tempranos inespecíficos y falta de características somáticas evidentes en comparación con otros tipos de MPS. Cuando se tiene el diagnóstico definitivo, es fundamental brindar atención interdisciplinaria para el paciente y la familia, y apoyar el tratamiento de los síntomas físicos, garantizando ofrecer el mejor cuidado posible y la mejor calidad de vida para el paciente y su familia, al tratarse de una condición neurodegenerativa.(AU)

Introduction: Mucopolysaccharidosis type III (MPS III), also known as Sanfilippo syndrome, is a lysosomal storage disease with progressive neurodegenerative features, predominantly affecting the central nervous system. Diagnosis is based on clinical features, with neurodevelopmental and neuropsychiatric alterations taking precedence, including over phenotype alterations. The disease is confirmed by biochemical analysis to identify the type of glycosaminoglycans present, enzyme assay and molecular genetic studies. Case reports: A clinical description was performed for eight patients diagnosed with MPS III in Colombia. Their initial symptoms were related to developmental delay and behavioural disorders presenting between 3 and 8 years of age, associated in all cases with coarse facial features, thick eyebrows, hepatomegaly and progressive hearing loss. One of the patients presented cardiac anomalies; two presented focal epilepsy; and one presented optic atrophy. They all presented neuroimaging alterations, with evidence of parenchymal volume loss, corpus callosum atrophy and cortical thinning; the diagnosis was performed by biochemical glycosaminoglycan chromatography studies, and all patients have a confirmatory genetic study. Conclusions: MPS III is a challenge for diagnosis, particularly in its early stages and in patients in which the course of the disease is attenuated. This is due to its variable course, non-specific early neuropsychiatric symptoms, and the absence of obvious somatic features compared to other types of MPS. After a definitive diagnosis has been made, interdisciplinary care must be provided for the patient and their family, and support given for the treatment of physical symptoms, ensuring the best possible care and quality of life for the patient and their family, as the condition is neurodegenerative.(AU)

Efficacy of a Combination Therapy with Laronidase and Genistein in Treating Mucopolysaccharidosis Type I in a Mouse Model.

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder caused by α-L-iduronidase deficiency. The standard treatment, enzyme replacement therapy with laronidase, has limited effectiveness in treating neurological symptoms due to poor blood-brain barrier penetration. An alternative is substrate reduction therapy using molecules, such as genistein, which crosses this barrier. This study evaluated the effectiveness of a combination of laronidase and genistein in a mouse model of MPS I. Over 12 weeks, MPS I and wild-type mice received laronidase, genistein, or both. Glycosaminoglycan (GAG) storage in visceral organs and the brain, its excretion in urine, and the serum level of the heparin cofactor II-thrombin (HCII-T) complex, along with behavior, were assessed. The combination therapy resulted in reduced GAG storage in the heart and liver, whereas genistein alone reduced the brain GAG storage. Laronidase and combination therapy decreased liver and spleen weights and significantly reduced GAG excretion in the urine. However, this therapy negated some laronidase benefits in the HCII-T levels. Importantly, the combination therapy improved the behavior of female mice with MPS I. These findings offer valuable insights for future research to optimize MPS I treatments.

Adenotonsillectomy for the treatment of OSA in children with mucopolysaccharidosis: A systematic review.

OBJECTIVE: To study the role of adenotonsillectomy (ADT) for obstructive sleep apnea (OSA) in children with mucopolysaccharidosis (MPS). METHODS: A systematic review were performed following the PRISMA guideline. PubMed and Embase were searched for studies regarding adenotonsillectomy for OSA in children with MPS. The MINOR Score were applied for quality assessment of the included studies. RESULTS: Nineteen studies were eligible for inclusion: fifteen were retrospective and four prospective. A total of 1406 subjects were included. The samples size varied from 2 to 336, the male to female ratio is 1.2 and mean age varied from 2.4 to 11 years. Overall, 56.2 % (IC 95%: 53.6-58.8) of the included subjects underwent ADT. MPS I and II are the two most operated types. Three studies, including 50 children, reported improvement in polysomnographic parameters after surgery. Two authors described the duration of follow-up: 8.4 and 9.8 years, respectively. CONCLUSIONS: More than half of children with MPS underwent ADT for the treatment of OSA, although few evidence demonstrated improvement in term of polysomnographic parameters. The two types of MPS most involved are type I and II. Considering the disease progression and anesthetic risks, multidisciplinary management may help identify the subgroup of children with MPS who benefit from ADT for the treatment of OSA.