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PURPOSE: To describe a case of retinitis pigmentosa and nanophthalmos in a patient with attenuated Hunter's syndrome. METHODS: Fundus photography, total field electroretinogram, ultrasound, computerized visual field examination, biochemical examination and genetic testing were obtained. RESULTS: The fundus exam showed diffuse arteriolar attenuation, optic disc with regular contours, and pigment agglomerates like "bone spicules" in the middle periphery. Ultrasound examination revealed scleral thickening and short axial diameter in both eyes. The total field electroretinogram exam showed a subnormal result with greater impairment of the scotopic phase of the exam. Computerized visual field examination demonstrated a diffuse reduction in retinal sensitivity in the periphery. Biochemical examination showed increased urine glycosaminoglycan excretion and iduronate-2-sulphatase activity (IDS) deficiency in leukocytes, confirming the type II mucopolysaccharidosis. Molecular analysis revealed a novel missense mutation (p.A77D) in the IDS gene. CONCLUSION: The case report is about a patient presented an attenuated form of the syndrome, with no cognitive impairment. Ophthalmologic follow-up is still an important part of multidisciplinary treatment for Hunter's syndrome.
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Microftalmia , Mucopolissacaridose II , Retinose Pigmentar , Humanos , Mucopolissacaridose II/complicações , Mucopolissacaridose II/diagnóstico , Mucopolissacaridose II/terapia , Microftalmia/complicações , Microftalmia/diagnóstico , Microftalmia/genética , Eletrorretinografia , Retinose Pigmentar/complicações , Retinose Pigmentar/diagnóstico , Retinose Pigmentar/genética , Mutação de Sentido IncorretoRESUMO
Abstract Data on Mucopolysaccharidosis type II (MPS II) in Latin America are scarce. This retrospective database study, using data from the Informatics Department of the Brazilian Health System (DATASUS), aimed to estimate the prevalence of MPSII in Brazil from 2008 to 2020 and to describe demographic and clinical profiles from patients under treatment. The study population was derived from DATASUS records of MPS II (ICD-10 E76.1) diagnosed in Brazil. Initially 455 patients were found, but only 181 patients who were receiving idursulfase treatment were included in this study. Among these cases, as expected in a X-linked disease, all were males and 40% of the cases were recorded in the Southeast region, and another 34% in the Northeast region. The biggest proportion of patients (39%) were diagnosed when they were 10-19 years old. There are 212 clinical conditions associated with MPS II, although the main comorbidities related to MPSII include: abdominal/inguinal hernia, respiratory complications, and carpal tunnel syndrome. Respiratory disorders were the fifth most frequent comorbidity recorded in these patients. The healthcare professionals in Brazil more involved in the diagnosis of MPS II were radiologists, followed by geneticists and cardiologists. Despite some limitations, DATASUS is a relevant database to provide information on rare diseases such as MPS II. Most cases were reported in southeast and northeast regions, respectively. This information is crucial to help design targeted public policies.
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Bow Hunter's syndrome is a rare cause of posterior circulation ischemia, produced by the mechanical and reversible occlusion of the vertebral artery during cephalic rotation. Diagnosis requires clinical suspicion and careful inspection of images with three-dimensional reconstruction. The study of choice is dynamic digital subtraction angiography (DSA). Treatment alternatives are: medical, surgical or endovascular. We report the case of an 8-year-old boy with recurrent infarctions of the posterior circulation secondary to the dissection of the vertebral artery, in association with an occipital bone spur. Dynamic DSA was negative. Conservative initial management was elected with cervical immobilization and anticoagulation, but due to persistence of symptoms, surgical decompression was decided. The patient did not repeat symptoms postoperatively and returned to his usual life. This is the first case reported to our knowledge of a surgical pediatric patient with asymptomatic atypical compression of VA secondary to BHS, whose dynamic angiography was negative, suggesting an alternative mechanism of the syndrome.
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Mucopolissacaridose II , Insuficiência Vertebrobasilar , Masculino , Humanos , Criança , Insuficiência Vertebrobasilar/diagnóstico por imagem , Insuficiência Vertebrobasilar/etiologia , Insuficiência Vertebrobasilar/cirurgia , Mucopolissacaridose II/complicações , Artéria Vertebral/diagnóstico por imagem , Artéria Vertebral/cirurgia , Descompressão Cirúrgica/métodos , Angiografia DigitalRESUMO
Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a rare X-linked recessive disease caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase (IDS), which activates intracellular accumulation of nonmetabolized glycosaminoglycans such as heparan sulfate and dermatan sulfate. This accumulation causes severe damage to several tissues, principally the central nervous system. Previously, we identified 187 IDS-protein interactions in the mouse brain. To validate a subset of these interactions, we selected and cloned the coding regions of 10 candidate genes to perform a targeted yeast two-hybrid assay. The results allowed the identification of the physical interaction of IDS with LSAMP and SYT1. Although the physiological relevance of these complexes is unknown, recent advances allow us to point out that these interactions could be involved in vesicular trafficking of IDS through the interaction with SYT1, as well as to the ability to form a transcytosis module between the cellular components of the blood-brain-barrier (BBB) through its interaction with LSAMP. These results may shed light on the role of IDS on cellular homeostasis and may also contribute to the understanding of MPS II physiopathology and the development of novel therapeutic strategies to transport recombinant IDS through the brain endothelial cells toward the brain parenchyma.
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Mucopolysaccharidosis type II is an X-linked lysosomal storage disorder caused by mutations in the IDS gene that encodes the iduronate-2-sulfatase enzyme. The IDS gene is located on the long arm of the X-chromosome, comprising 9 exons, spanning approximately 24 kb. The analysis of carriers, in addition to detecting mutations in patients, is essential for genetic counseling, since the risk of recurrence for male children is 50%. Mosaicism is a well-known phenomenon described in many genetic disorders caused by a variety of mechanisms that occur when a mutation arises in the early development of an embryo. Sanger sequencing is limited in detecting somatic mosaicism and sequence change levels of less than 20% may be missed. The Next Generation Sequencing (NGS) has been increasingly used in diagnosis. It is a sensitive and fast method for the detection of somatic mosaicism. Compared to Sanger sequencing, which represents a cumulative signal, NGS technology analyzes the sequence of each DNA read in a sample. NGS might therefore facilitate the detection of mosaicism in mothers of MPS II patients. The aim of this study was to reanalyze, by NGS, all MPS II mothers that showed to be non-carriers by Sanger analysis. Twelve non-carriers were selected for the reanalysis on the Ion PGM and Ion Torrent S5 platform, using a custom panel that includes the IDS gene. Results were visualized in the Integrative Genomics Viewer (IGV). We were able to detected the presence of the variant previously found in the index case in three of the mothers, with frequencies ranging between 13 and 49% of the reads. These results suggest the possibility of mosaicism in the mothers. The use of a more sensitive technology for detecting low-level mosaic mutations is essential for accurate recurrence-risk estimates. In our study, the NGS analysis showed to be an effective methodology to detect the mosaic event.
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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.
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Terapia de Reposição de Enzimas , Iduronato Sulfatase/uso terapêutico , Mucopolissacaridose II/tratamento farmacológico , Animais , Biomarcadores/líquido cefalorraquidiano , Barreira Hematoencefálica/efeitos dos fármacos , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Ensaios Clínicos como Assunto , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Humanos , Iduronato Sulfatase/genética , Iduronato Sulfatase/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucopolissacaridose II/patologia , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Índice de Gravidade de DoençaRESUMO
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.
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Mucopolissacaridose II , Brasil , Genótipo , Humanos , Masculino , Mucopolissacaridose II/genética , Mutação , FenótipoRESUMO
Objetivo: Describir las características bucales prevalentes de pacientes argentinos con mucopolisacaridosis (MPS) atendidos en el Servicio de Odontología del Hospital Nacional "Prof. Alejandro Posadas". Materiales y métodos: Se consideraron las historias clínicas de 19 pacientes con diagnóstico de MPS. Se registraron la edad, el sexo, el lugar de residencia, el tipo de MPS y la presencia de retraso madurativo. La muestra estuvo constituida por 13 niños (6,7±3 años) y 6 adultos (26±9 años): 2 eran mujeres (1 con MPS tipo I; 1 con MPS tipo IV A) y 17 eran hombres (15 con MPS tipo 2; 1 con MPS tipo 1; 1 con MPS tipo III); 13 de los pacientes presentaban discapacidad intelectual. Se evaluaron: tipo de dentición, oclusión, macroglosia, hipoplasias del esmalte, tipo de respiración predominante, clase molar y tratamiento realizado. Resultados: Ambos casos con MPS I presentaban mordida abierta anterior y giroversión dental, y solo uno de estos, diastemas, microdoncia, hipoplasias del esmalte, macroglosia y respiración bucal. De los 15 pacientes con MPS II, 11 presentaban mordida abierta anterior (73%), 3 mordida cruzada posterior (20%), 5 giroversión dental (33%), 11 diastemas (73%), 3 retraso en la erupción (20%), 4 hiperplasia gingival (26%), 13 macroglosia (87%), 7 hipoplasias del esmalte (47%), 2 microdoncia (13%), 9 respiración bucal (60%). Se registraron 5 pacientes con clase molar I (33%), 3 con clase molar II (20%), 3 con clase molar III (20%) y en 3 casos no se pudo evaluar (20%). En el paciente con MPS tipo III se halló mordida abierta anterior, diastemas, retraso en la erupción, macroglosia, respiración bucal y clase molar II; y en el caso de MPS tipo IV A, mordida abierta anterior, diastemas, hiperplasia gingival, macroglosia y clase molar II. El 90% de los pacientes requirió tratamiento odontológico (AU)
Aim: To identify the most prevalent oral manifestations of 19 Argentine patients with mucopolysaccharidos (MPS) attending the Dentistry Service of the National Posadas Hospital. Materials and methods: The medical records of 19 patients diagnosed with MPS were considered. Age, sex, place of residence, type of MPS, and presence of maturational delay were recorded. The sample consisted of 13 children (6.7 ± 3 years) and 6 adults (26 ± 9 years): 2 were women (1 with MPS type I; 1 with MPS type IV A) and 17 were men (15 with MPS type 2; 1 with MPS type 1; 1 with MPS type III); 13 of the patients had intellectual disabilities. The following were evaluated: type of dentition, occlusion, macroglossia, enamel hypoplasia, predominant type of respiration, molar class and treatment performed Results: Both cases with MPS I presented anterior open bite and dental gyroversion, and only one of these, diastemas, microdontia, enamel hypoplasia, macroglossia and mouth respiration. Of the 15 patients with MPS II, 11 presented anterior open bite (73%), 3 posterior crossbite (20%), 5 dental gyroversion (33%), 11 diastemas (73%), 3 delayed eruption (20%), 4 gingival hyperplasia (26%), 13 macroglossia (87%), 7 enamel hypoplasia (47%), 2 microdontia (13%), 9 mouth breathing (60%). 5 patients with molar class I (33%), 3 with molar class II (20%), 3 with molar class III (20%) and in 3 cases it could not be evaluated (20%). In the patient with type III MPS, anterior open bite, diastemas, delayed eruption, macroglossia, mouth breathing and molar class II were found; and in the case of type IV A MPS, anterior open bite, diastemas, gingival hyperplasia, macroglossia and molar class II. 90% of the patients required dental treatment. Conclusion: The most observed oral manifestations were macroglossia (84.2%) and anterior open bite (73%) (AU)
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Humanos , Masculino , Feminino , Criança , Adolescente , Adulto , Manifestações Bucais , Mucopolissacaridose II/patologia , Mucopolissacaridose I/patologia , Mucopolissacaridose III/patologia , Argentina , Epidemiologia Descritiva , Estudos Transversais , Mordida Aberta/epidemiologia , Unidade Hospitalar de Odontologia/estatística & dados numéricos , Distribuição por Idade e Sexo , Macroglossia/epidemiologia , Má Oclusão/epidemiologiaRESUMO
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.
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Anticorpos Monoclonais/administração & dosagem , Terapia de Reposição de Enzimas/métodos , Iduronato Sulfatase/administração & dosagem , Mucopolissacaridose II/tratamento farmacológico , Receptores da Transferrina/antagonistas & inibidores , Proteínas Recombinantes de Fusão/administração & dosagem , Adolescente , Adulto , Brasil/epidemiologia , Criança , Quimioterapia Combinada , Feminino , Humanos , Masculino , Mucopolissacaridose II/epidemiologia , Mucopolissacaridose II/genética , Mucopolissacaridose II/patologia , Receptores da Transferrina/imunologia , Resultado do Tratamento , Adulto JovemRESUMO
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.