Taiane Alves Vieira

Intrathecal enzyme replacement therapy in a patient with mucopolysaccharidosis type I and symptomatic spinal cord compression

In mucopolysaccharidosis I, deficiency of α‐L‐iduronidase can cause spinal cord compression (SCC) due to storage of glycosaminoglycans (GAGs) within the cervical meninges. As intravenous enzyme replacement therapy (ERT) is not likely to provide enzyme across the blood–brain barrier, standard treatment for this complication is usually surgical, which has a high morbidity and mortality risk. We report on the use of intrathecal (IT) laronidase in a MPS I patient with SCC who refused the surgical treatment. Assessments were performed at baseline, with clinical and biochemical evaluations, 4‐extremity somatosensory evoked potentials, 12 min walk test and MRI studies of the CNS. Changes on these parameters were evaluated after 4 IT infusions of laronidase administered monthly via lumbar puncture. To our knowledge, this was the first MPS patient who received IT ERT. No major adverse events were observed. There were no clinically significant changes in serum chemistries. CSF GAG results revealed pretreatment values slightly above normal standards: 13.3 mg/L (NV < 12 mg/L) which after IT laronidase infusions were within normal levels (10.3 mg/L). 12MWT presented a 14% improvement, with better performance on stability and gait control. Maximum voluntary ventilation showed 55.6% improvement considering the percentage of predicted (26.7% at baseline compared to 41.9%); Maximum Inspiration Pressure improved 36.6% of predicted (26.8% at baseline to 36.7%); Pulmonary diffusion improved 17.6% of predicted %. In conclusion, although the improvement observed in this case with IT laronidase should be confirmed in further patients, this procedure seems to be a safe treatment for SCC in MPS I.

Intrathecal administration of recombinant human N-acetylgalactosamine 4-sulfatase to a MPS VI patient with pachymeningitis cervicalis.

In mucopolysaccharidosis VI, or Maroteaux-Lamy syndrome, deficiency of N-acetylgalactosamine 4-sulfatase leads to storage of glycosaminoglycans (GAGs) and MPS VI patients often develop spinal cord compression during the course of the disease due to GAG storage within the cervical meninges, requiring neurosurgical intervention, as intravenous (IV) enzyme replacement therapy (ERT) is not expected to cross the blood-brain barrier. We report the use of intrathecal (IT) recombinant human N-acetylgalactosamine 4-sulfatase (arylsulfatase B, or ASB) in a MPS VI child with spinal cord compression whose parents initially refused the surgical treatment. Assessments were performed at baseline, with clinical, neurological and biochemical evaluations, urodynamic studies and MRI of the CNS. Changes on these parameters were evaluated after IT infusions of ASB administered monthly via lumbar puncture (LP) in a IV ERT naive patient. To our knowledge, this was the first MPS VI patient who received IT ERT. Despite significant urodynamic improvement and some neurological amelioration, the patient developed worsening of walking capacity. After IV ERT was started, the patient presented with a generalized hypotonia and a life-saving surgical fixation of the neck was then performed. The results observed on this MPS VI patient suggest that instability of the cervical vertebrae could be unmasked by IV ERT as joint storage is reduced, and the decrease in neck stiffness and stability could confound the expected improvement of SCC manifestations following IT ERT. The study of further patients, if possible in a clinical trial setting, is needed to evaluate the potential of a non-surgical IT ERT treatment of SCC for MPS VI.

Mucopolysaccharidoses in Brazil: what happens from birth to biochemical diagnosis?

Mucopolysaccharidoses (MPS) form a group of inherited metabolic disorders characterized by intralysosomal storage of glycosaminoglycans. This study aimed to investigate the path followed by Brazilian patients from birth to diagnosis. An interview was conducted with patients parents or guardians with subsequent review of patients medical records. One hundred thirteen patients with MPS were included (MPS I: 18, MPS II: 43, MPS IIIA: 2, MPS IIIB: 3, MPS IIIC: 1, MPS IVA: 15, MPS IVB: 1, MPS VI: 29, MPS VII: 1) from 97 families. Median age at the onset of signs/symptoms was 18 months (MPS I: 18, MPS II: 24, MPS IVA: 8, MPS VI: 8). Skeletal abnormalities (for MPS IVA and MPS VI), joint contractures (for MPS II), and typical facial features (for MPS I) were the most frequently reported first signs/symptoms. Several health professionals were involved in patients care as of the onset of symptoms until biochemical diagnosis was established. Median age at diagnosis was 76 months (MPS I: 75, MPS II: 95, MPS IVA: 75, MPS VI: 52). Considering the group as a whole, there was a 4.8‐year delay between the onset of signs/symptoms and the establishment of the diagnosis. Considering that specific therapies are available for some of these disorders and that early treatment is likely to change more favorably the natural history of the disease, efforts should be made to minimize this delay. We believe that this situation can be improved by measures that both increase awareness of health professionals about MPS and improve access to diagnostic tests.

Expression of the disease on female carriers of X-linked lysosomal disorders: a brief review

Most lysosomal diseases (LD) are inherited as autosomal recessive traits, but two important conditions have X-linked inheritance: Fabry disease and Mucopolysaccharidosis II (MPS II). These two diseases show a very different pattern regarding expression on heterozygotes, which does not seem to be explained by the X-inactivation mechanism only. While MPS II heterozygotes are asymptomatic in most instances, in Fabry disease most of female carriers show some disease manifestation, which is sometimes severe. It is known that there is a major difference among X-linked diseases depending on the cell autonomy of the gene product involved and, therefore, on the occurrence of cross-correction. Since lysosomal enzymes are usually secreted and uptaken by neighbor cells, the different findings between MPS II and Fabry disease heterozygotes can also be due to different efficiency of cross-correction (higher in MPS II and lower in Fabry disease). In this paper, we review these two X-linked LD in order to discuss the mechanisms that could explain the different rates of penetrance and expressivity observed in the heterozygotes; this could be helpful to better understand the expression of X-linked traits.

Practical and reliable enzyme test for the detection of Mucopolysaccharidosis IVA (Morquio Syndrome type A) in dried blood samples

BACKGROUND Mucopolysaccharidosis IVA (MPS IVA), or Morquio Syndrome type A, is an autosomal recessive disease caused by deficiency of the lysosomal enzyme N-acetylgalactosamine-6-sulfatase (GALNS), resulting in excessive lysosomal storage of keratan sulfate in many tissues and organs. This accumulation causes a severe skeletal dysplasia with short stature, and affects the eye, heart and other organs, with many signs and symptoms. Morquio A syndrome is estimated to occur in 1 in 200,000 to 300,000 live births. Clinical trials with enzyme replacement therapy for this disease are in progress, and it is probable that the treatment, when available, would be more effective if started early. We describe an innovative fluorometric method for the assay of GALNS in dried blood spots (DBS). METHODS We used dried blood spots (DBS) as the enzyme source and compared it with leukocytes samples, having studied 25 MPS IVA patients and 54 healthy controls. We optimized the assay conditions, including incubation time and stability of DBS samples. To eppendorf type tubes containing a 3-mm diameter blood spot we added elution liquid and substrate solution. After 2 different incubations at 37°C, the amount of hydrolyzed product was compared with a calibrator to allow the quantification of the enzyme activity. Results in DBS were compared to the ones obtained in leukocytes using the standard technique. RESULTS The fluorescent methodology was validated in our laboratory and the assay was found sensitive and specific, allowing reliable detection of MPS IVA patients. The use of DBS simplifies the collection and transport steps, and is especially useful for testing patients from more remote areas of large countries, and when samples need to cross country borders. CONCLUSION This assay could be easily incorporated into the protocol of reference laboratories and play a role in the screening for MPS IVA, contributing to earlier detection of affected patients.

Prospective study of 11 Brazilian patients with mucopolysaccharidosis II

OBJECTIVE To assess the progression of mucopolysaccharidosis II in 11 Brazilian patients over a 12-month period. METHODS Eleven Brazilian patients with mucopolysaccharidosis II were prospectively studied at the Division of Medical Genetics of Hospital de Clínicas de Porto Alegre. The initial assessment and the assessment at 12 months included: anamnesis, physical examination, abdominal nuclear magnetic resonance, echocardiogram, 6-minute walk test, audiometry, serum biochemical tests and urinary glycosaminoglycan concentration. RESULTS The major findings after comparing the assessments were: 1) two patients had growth retardation; 2) two patients showed negative weight change; 3) one patient went from obese to overweight; 4) three patients revealed left ventricle hypertrophy; of these, two increased the number of cardiac valve lesions; 5) there was no statistically significant difference between the mean distances obtained on the 6-minute walk test; 6) there was splenic enlargement; 7) there was an increase in gamma-glutamyltransferase levels; 8) the urinary concentration of glycosaminoglycans remained unchanged. CONCLUSIONS In general, echocardiographic findings were the only variable with deterioration and possible immediate clinical consequences. Although a 12-month period is too short to detect changes in most variables related to mucopolysaccharidosis II, its progressive nature should be taken into account when evaluating the efficiency of treatment protocols.

Terapia de reposição enzimática para as mucopolissacaridoses I, II e VI: recomendações de um grupo de especialistas brasileiros

Mucopolysaccharidoses (MPS) are rare genetic diseases caused by deficiency of specific lysosomal enzymes that affect catabolism of glycosaminoglycans (GAG). Accumulation of GAG in various organs and tissues in MPS patients results in a series of signs and symptoms, producing a multisystemic condition affecting bones and joints, the respiratory and cardiovascular systems and many other organs and tissues, including in some cases, cognitive performance. So far, eleven enzyme defects that cause seven different types of MPS have been identified. Before introduction of therapies to restore deficient enzyme activity, treatment of MPS focused primarily on prevention and care of complications, still a very important aspect in the management of these patients. In the 80s treatment of MPS with bone marrow transplantation/hematopoietic stem cells transplantation (BMT/HSCT) was proposed and in the 90s, enzyme replacement therapy (ERT),began to be developed and was approved for clinical use in MPS I, II and VI in the first decade of the 21st century. The authors of this paper are convinced that a better future for patients affected by mucopolysaccharidoses depends upon identifying, understanding and appropriately managing the multisystemic manifestations of these diseases. This includes the provision of support measures (which should be part of regular multidisciplinary care of these patients) and of specific therapies. Although inhibition of synthesis of GAG and the recovery of enzyme activity with small molecules also may play a role in the management of MPS, the breakthrough is the currently available intravenous ERT. ERT radically changed the setting for treatment of mucopolysaccharidosis I, II and VI in the last decade., Benefits can even be extended soon to MPS IV A (ERT for this condition is already in clinical development), with prediction for treatment of MPS III A and the cognitive deficit in MPS II by administration of the enzyme directly into the central nervous system (CNS). A large number of Brazilian services, from all regions of the country, already have experience with ERT for MPS I, II and VI. This experience was gained not only by treating patients but also with the participation of some groups in clinical trials involving ERT for these conditions. Summing up the three types of MPS, more than 250 patients have already been treated with ERT in Brazil. The experience of professionals coupled to the data available in international literature, allowed us to elaborate this document, produced with the goal of bringing together and harmonize the information available for the treatment of these severe and progressive diseases, which, fortunately, are now treatable, a situation which bring new perspectives for Brazilian patients, affected by these conditions.As mucopolissacaridoses (MPS) sao doencas geneticas raras causadas pela deficiencia de enzimas lisossomicas especificas que afetam o catabolismo de glicosaminoglicanos (GAG). O acumulo de GAG em varios orgaos e tecidos nos pacientes afetados pelas MPS resulta em uma serie de sinais e sintomas, integrantes de um quadro clinico multissistemico que compromete ossos e articulacoes, vias respiratorias, sistema cardiovascular e muitos outros orgaos e tecidos, incluindo, em alguns casos, as funcoes cognitivas. Ja foram identificados 11 defeitos enzimaticos que causam sete tipos diferentes de MPS. Antes do advento de terapias dirigidas para a restauracao da atividade da enzima deficiente, o tratamento das MPS tinha como principal foco a prevencao e o cuidado das complicacoes, aspecto ainda bastante importante no manejo desses pacientes. Na decada de 80 foi proposto o tratamento das MPS com transplante de medula ossea/transplante de celulas tronco hematopoieticas (TMO/TCTH) e na decada de 90 comecou o desenvolvimento da Terapia de Reposicao Enzimatica (TRE), que se tornou uma realidade aprovada para uso clinico nas MPS I, II e VI na primeira decada do seculo 21. Os autores deste trabalho tem a conviccao de que um melhor futuro para os pacientes afetados pelas MPS depende da identificacao, compreensao e manejo adequado das manifestacoes multissistemicas dessas doencas, incluindo medidas de suporte (que devem fazer parte da assistencia multidisciplinar regular destes pacientes) e terapias especificas. Embora a inibicao da sintese de GAG e o resgate da atividade enzimatica com moleculas pequenas tambem possam vir a ter um papel no manejo das MPS, o grande avanco disponivel no momento e a TRE intravenosa. A TRE permitiu modificar radicalmente o panorama do tratamento das mucopolissacaridoses I, II e VI na ultima decada, sendo que ainda pode estender seus beneficios em breve para a MPS IV A (cuja TRE ja esta em desenvolvimento clinico), com perspectivas para o tratamento da MPS III A e do deficit cognitivo na MPS II atraves de administracao da enzima diretamente no sistema nervoso central (SNC). Um grande numero de centros brasileiros, incluindo servicos de todas as regioes do pais, ja tem experiencia com TRE para MPS I, II e VI. Essa experiencia foi adquirida nao so com o tratamento de pacientes como tambem com a participacao de alguns grupos em ensaios clinicos envolvendo TRE para essas condicoes. Somados os tres tipos de MPS, mais de 250 pacientes ja foram tratados com TRE em nosso pais. A experiencia dos profissionais brasileiros, somada aos dados disponiveis na literatura internacional, permitiu elaborar este documento, produzido com o objetivo de reunir e harmonizar as informacoes disponiveis sobre o tratamento destas doencas graves e progressivas, mas que, felizmente, sao hoje trataveis, uma realidade que traz novas perspectivas para os pacientes brasileiros afetados por essas condicoes.

Avaliação prospectiva de 11 pacientes brasileiros com mucopolissacaridose II

OBJETIVO: Avaliar a progressao da mucopolissacaridose II, durante um periodo de 12 meses, em 11 pacientes brasileiros. METODOS: Onze pacientes brasileiros com mucopolissacaridose II foram avaliados prospectivamente no Servico de Genetica Medica do Hospital de Clinicas de Porto Alegre. As avaliacoes realizadas na visita inicial e na de 12 meses foram: anamnese, exame fisico, ressonância nuclear magnetica abdominal, ecocardiograma, teste da caminhada em 6 minutos, audiometria, exames bioquimicos sericos e dosagem urina- ria de glicosaminoglicanos. RESULTADOS: Os principais achados relativos a comparacao entre as duas visitas foram: 1) dois pacientes apresentaram retardo de crescimento; 2) dois pacientes apresentaram variacao negativa em relacao ao peso; 3) um paciente apresentou variacao de obesidade para sobrepeso; 4) tres pacientes desenvolveram alargamento do ventriculo esquerdo; destes, dois aumentaram o numero de lesoes nas valvas cardiacas; 5) nao foi encontrada diferenca estatistica significativa entre a media das distâncias percorridas no teste da caminhada em 6 minutos; 6) houve aumento do volume esplenico; 7) ocorreu aumento dos niveis de gamaglutamiltransferase; 8) nao houve alteracao dos niveis urinarios de glicosaminoglicanos. CONCLUSOES: De uma maneira geral, a unica variavel que apresentou, no periodo estudado, piora com potencial repercussao clinica imediata foram os achados ecocardiograficos. Embora o periodo de 12 meses seja curto para medir alteracoes na maioria dos parâmetros comprometidos na mucopolissacaridose II, sua natureza progressiva deve ser levada em conta na avaliacao da eficacia dos protocolos de tratamento para essa condicao.

Inclusion of medical genetics in primary health care: report of a pilot project in Brazil

Over the past few decades, several advances have been made in our knowledge of the genetic basis of diseases, prompting particular attention to the prevention and control of this determinant and to the adequate management of those affected or at risk of developing genetic conditions. The causes of genetic disease are manifold, and a variety of approaches are thus required for their prevention and to ensure better care of patients and families. In 2000, the World Health Organization (WHO) proposed that interventions for prevention and control of genetic disorders and congenital malformations should be added to the primary health care (PHC) framework (WHO 2000). The main characteristic of PHC is its status as the first contact to the health system, providing comprehensive, continuous care over time and coordinating the care received by individuals and families at the various points of care throughout the health system. Other defining characteristics of PHC include its family- and community-oriented nature and cultural competence (Starfield 1992). At the interface between genetics and PHC is the field of community genetics. In 1998, Leo ten Kate defined community genetics as “bringing genetic services to the community as a whole.” (ten Kate 1998) The author later expanded this definition, describing community genetics as “the art and science of the responsible and realistic application of health and disease-related genetics and genomics knowledge and technologies in human populations and communities to the benefit of individuals therein. Community genetics is multi-, inter- and transdisciplinary and aims to maximize benefits while minimizing the risk of harm, respecting the autonomy of individuals and ensuring equity” (ten Kate et al. 2010). Within this context, several efforts have been made in the direction of integrating basic knowledge of genetics into the framework of PHC. Education is viewed as the key for preparing primary care providers for a reality in which genetics will be present in the daily routine of health care and disease prevention (Khoury 2003). Genetic diseases contribute significantly to the population-wide disease burden, and primary care providers have an important role to play in their prevention and in the identification of patients that could benefit from referral to medical genetics services, as they will remain responsible for the care of these patients throughout the life course (Burke and Emery 2002). In 2009, the Brazilian government published its national policy for comprehensive clinical genetics care (Brasil 2009). This policy includes both specialty medical genetics care and primary care. In the latter setting, the policy provides for identification and follow-up of families with conditions related to congenital anomalies and genetically determined diseases. The objective of this study was to ascertain whether implementation of a medical genetics education program produced for primary care providers could contribute to the integration of concepts and attitudes related to the identification, management, and prevention of congenital malformations and genetic diseases into the care provided at primary health care units.

Immune tolerance induction for laronidase treatment in mucopolysaccharidosis I.

Enzyme replacement therapy (ERT) can produce anti-drug antibody (ADA) responses that reduce efficacy or lead to hypersensitivity reactions. Six patients with severe mucopolysaccharidosis type I (MPS I/Hurler syndrome) who did not receive hematopoietic stem cell transplantation underwent an immunosuppression regimen prior to initiating ERT with laronidase. The primary endpoint for immune tolerance induction was the number of patients with an ADA titer ≤ 3200 after 24 weeks of laronidase at the labeled dose. Cyclosporine levels were measured weekly and doses adjusted to maintain trough levels above 400 mg/mL. A 6-week (Cohort 1) or 12-week (Cohort 2) immune tolerance induction period with cyclosporine (initial dose: 15 or 20 mg/kg/day), azathioprine (initial dose: 2.5 or 5 mg/kg/day) and low-dose laronidase infusions (0.058–0.29 mg/kg/week) was followed by an immune-challenge period with laronidase infusions at the labeled dose (0.58 mg/kg/week) for 24 weeks. Anti-laronidase IgG titers were determined following treatment. There were 147 treatment-emergent adverse events reported, most of which were mild and not related to the study treatment. While there was no evidence of immune tolerance in 3 of 3 patients in Cohort 1, there were some indications of immune tolerance induction in 2 of 3 patients in Cohort 2. Patients with lower ADA titers showed greater reductions in urinary glycosaminoglycan excretion. Routine monitoring of plasma cyclosporine parent-compound levels by high pressure liquid chromatography proved difficult for clinical practice. The evolving clinical management of MPS I and a better understanding of the clinical impact of laronidase-related immunogenicity require reassessment of immune modulation strategies in patients with MPS I receiving laronidase treatment. Clinical Trial Registration: NCT00741338.