Pathogenic variants in GNPTAB and GNPTG encoding distinct subunits of GlcNAc-1-phosphotransferase differentially impact bone resorption in patients with mucolipidosis type II and III.

PURPOSE: Pathogenic variants in GNPTAB and GNPTG, encoding different subunits of GlcNAc-1-phosphotransferase, cause mucolipidosis (ML) II, MLIII alpha/beta, and MLIII gamma. This study aimed to investigate the cellular and molecular bases underlying skeletal abnormalities in patients with MLII and MLIII. METHODS: We analyzed bone biopsies from patients with MLIII alpha/beta or MLIII gamma by undecalcified histology and histomorphometry. The skeletal status of Gnptgko and Gnptab-deficient mice was determined and complemented by biochemical analysis of primary Gnptgko bone cells. The clinical relevance of the mouse data was underscored by systematic urinary collagen crosslinks quantification in patients with MLII, MLIII alpha/beta, and MLIII gamma. RESULTS: The analysis of iliac crest biopsies revealed that bone remodeling is impaired in patients with GNPTAB-associated MLIII alpha/beta but not with GNPTG-associated MLIII gamma. Opposed to Gnptab-deficient mice, skeletal remodeling is not affected in Gnptgko mice. Most importantly, patients with variants in GNPTAB but not in GNPTG exhibited increased bone resorption. CONCLUSION: The gene-specific impact on bone remodeling in human individuals and in mice proposes distinct molecular functions of the GlcNAc-1-phosphotransferase subunits in bone cells. We therefore appeal for the necessity to classify MLIII based on genetic in addition to clinical criteria to ensure appropriate therapy.

Use of a multiplex ligation-dependent probe amplification method for the detection of deletions/duplications in the GBA1 gene in Gaucher disease patients.

Gaucher disease (GD) is caused by the deficient activity of ß-glucocerebrosidase due to pathogenic mutations in the GBA1. This gene has a pseudogene (GBAP) with 96% of sequence homology. Recombination (Rec) events in the GBA1 seem to be facilitated by an increased degree of homology and proximity to the GBAP. The objectives of this study were to validate the P338-X1 GBA kit (MRC-Holland) for Multiplex Ligation-dependent Probe Amplification (MLPA) and to detect larger deletions/duplications present in GBA1 in GD patients from Brazil. Thirty-three unrelated Brazilian GD patients, previously genotyped by the Sanger method (both pathogenic alleles identified=29 patients, only one allele identified=3 patients, no pathogenic alleles identified=1 patient), were evaluated by the MLPA assay. MLPA was compatible with the previous results obtained by Sanger sequencing and identified an additional allele (a heterozygous deletion in intron 7 in one patient with only one mutation identified by Sanger). Our data suggest that, although larger deletions/duplications do not appear to be frequent in GD, the P338-X1 GBA kit for MLPA appears to be a good method for GBA1 analysis. Additional investigations should be performed in order to characterize the remaining four uncharacterized alleles of our sample.

Enzyme replacement therapy for Mucopolysaccharidosis Type I among patients followed within the MPS Brazil Network.

Mucopolysaccharidosis type I (MPS I) is a rare lysosomal disorder caused by deficiency of alpha-L-iduronidase. Few clinical trials have assessed the effect of enzyme replacement therapy (ERT) for this condition. We conducted an exploratory, open-label, non-randomized, multicenter cohort study of patients with MPS I. Data were collected from questionnaires completed by attending physicians at the time of diagnosis (T1; n = 34) and at a median time of 2.5 years later (T2; n = 24/34). The 24 patients for whom data were available at T2 were allocated into groups: A, no ERT (9 patients; median age at T1 = 36 months; 6 with severe phenotype); B, on ERT (15 patients; median age at T1 = 33 months; 4 with severe phenotype). For all variables in which there was no between-group difference at baseline, a delta of ≥ ± 20% was considered clinically relevant. The following clinically relevant differences were identified in group B in T2: lower rates of mortality and reported hospitalization for respiratory infection; lower frequency of hepatosplenomegaly; increased reported rates of obstructive sleep apnea syndrome and hearing loss; and stabilization of gibbus deformity. These changes could be due to the effect of ERT or of other therapies which have also been found more frequently in group B. Our findings suggest MPS I patients on ERT also receive a better overall care. ERT may have a positive effect on respiratory morbidity and overall mortality in patients with MPS I. Additional studies focusing on these outcomes and on other therapies should be performed.

A cohort study of neurodevelopmental disorders and/or congenital anomalies using high resolution chromosomal microarrays in southern Brazil highlighting the significance of ASD.

Chromosomal microarray (CMA) is the reference in evaluation of copy number variations (CNVs) in individuals with neurodevelopmental disorders (NDDs), such as intellectual disability (ID) and/or autism spectrum disorder (ASD), which affect around 3-4% of the world's population. Modern platforms for CMA, also include probes for single nucleotide polymorphisms (SNPs) that detect homozygous regions in the genome, such as long contiguous stretches of homozygosity (LCSH). These regions result from complete or segmental chromosomal homozygosis and may be indicative of uniparental disomy (UPD), inbreeding, population characteristics, as well as replicative DNA repair events. In this retrospective study, we analyzed CMA reading files requested by geneticists and neurologists for diagnostic purposes along with available clinical data. Our objectives were interpreting CNVs and assess the frequencies and implications of LCSH detected by Affymetrix CytoScan HD (41%) or 750K (59%) platforms in 1012 patients from the south of Brazil. The patients were mainly children with NDDs and/or congenital anomalies (CAs). A total of 206 CNVs, comprising 132 deletions and 74 duplications, interpreted as pathogenic, were found in 17% of the patients in the cohort and across all chromosomes. Additionally, 12% presented rare variants of uncertain clinical significance, including LPCNVs, as the only clinically relevant CNV. Within the realm of NDDs, ASD carries a particular importance, owing to its escalating prevalence and its growing repercussions for individuals, families, and communities. ASD was one clinical phenotype, if not the main reason for referral to testing, for about one-third of the cohort, and these patients were further analyzed as a sub-cohort. Considering only the patients with ASD, the diagnostic rate was 10%, within the range reported in the literature (8-21%). It was higher (16%) when associated with dysmorphic features and lower (7%) for "isolated" ASD (without ID and without dysmorphic features). In 953 CMAs of the whole cohort, LCSH (≥ 3 Mbp) were analyzed not only for their potential pathogenic significance but were also explored to identify common LCSH in the South Brazilians population. CMA revealed at least one LCSH in 91% of the patients. For about 11.5% of patients, the LCSH suggested consanguinity from the first to the fifth degree, with a greater probability of clinical impact, and in 2.8%, they revealed a putative UPD. LCSH found at a frequency of 5% or more were considered common LCSH in the general population, allowing us to delineate 10 regions as potentially representing ancestral haplotypes of neglectable clinical significance. The main referrals for CMA were developmental delay (56%), ID (33%), ASD (33%) and syndromic features (56%). Some phenotypes in this population may be predictive of a higher probability of indicating a carrier of a pathogenic CNV. Here, we present the largest report of CMA data in a cohort with NDDs and/or CAs from the South of Brazil. We characterize the rare CNVs found along with the main phenotypes presented by each patient and show the importance and usefulness of LCSH interpretation in CMA results that incorporate SNPs, as well as we illustrate the value of CMA to investigate CNV in ASD.

Quality of life of Brazilian families who have children with Fragile X syndrome: a descriptive study.

This study aimed to assess the Family Quality of Life (FQoL) of Brazilian families with male children with Fragile X syndrome (FXS). Data from 53 families were collected using forms that included sociodemographic and clinical information, as well as the Beach Center Family Quality of Life Scale, a 5-point Likert scale ranging from "very dissatisfied" (1) to "very satisfied" (5). The mean overall FQoL score was 3.56 ± 0.79; the emotional well-being domain had the lowest score (2.98 ± 1.11) and showed significant differences between the other domains: family interaction (3.81 ± 0.89; p < 0.001), parenting (3.66 ± 0.89; p < 0.001), physical and material well-being (3.48 ± 0.83; p < 0.001), and disability-related support (3.75 ± 0.98; p < 0.001). Physical and material well-being was the second-lowest domain and was statistically different from the family interaction domain (p = 0.013). Lower FQoL satisfaction ratings were found in families with children who had difficulty getting along with people of the same age (t(51) = -3.193, p = 0.002; d = 1.019) and difficulty in living together on a day-to-day basis (t(51) = -3.060, p = 0.004; d = 0.888). These results highlight the importance of proper emotional support for the family, emphasizing the need to provide assistance not only for individuals with FXS but also for other family members. Besides, we advocate for the adoption of public policies that provide financial assistance to families and the implementation of the Brazilian Policy of Comprehensive Care for People with Rare Diseases.

Are MPS II heterozygotes actually asymptomatic? A study based on clinical and biochemical data, X-inactivation analysis and imaging evaluations.

For some X-linked disorders the expressivity and penetrance in females are almost similar to those ones found in males. For mucopolysaccharidosis type II (MPS II), there are no studies in the literature trying to identify subtle signs and symptoms of this disease in heterozygotes. The objective of this study was to compare heterozygotes and non-heterozygotes for MPS II, in order to test the hypothesis that heterozygotes may present subtle manifestations of the disease. In this observational and transversal study we collected data on 40 Brazilian women with a positive familial history for MPS II that included clinical and physical exam, karyotype, pattern of X-inactivation, iduronate-2-sulfatase (IDS) activity in leukocytes and plasma, urinary glycosaminoglycans levels, computerized tomography scans (CT) of abdomen and spine, and brain magnetic resonance imaging. The Results showed the following: According to DNA analysis, 22 women were classified as heterozygote and 18 as non-heterozygotes. We did not find any abnormality on physical examination, karyotype, or spine CT. Also the pattern of X-inactivation was not different between the groups. Applying the Bonferroni's correction, both groups were found to differ only in relation to IDS activity in plasma and in leukocyte, which were lower in heterozygotes. In our investigation we did not find any evidence of subtle clinical manifestations of MPS II in heterozygotes. Our findings suggest there is no relation between the absence of clinical signs in these women and the occurrence of a favorable skewing pattern of X-inactivation.

Long contiguous stretches of homozygosity detected by chromosomal microarrays (CMA) in patients with neurodevelopmental disorders in the South of Brazil.

BACKGROUND: Currently, chromosomal microarrays (CMA) are recommended as first-tier test in the investigation of developmental disorders to examine copy number variations. The modern platforms also include probes for single nucleotide polymorphisms (SNPs) that detect homozygous regions in the genome, such as long contiguous stretches of homozygosity (LCSH) also named runs of homozygosity (ROH). LCHS are chromosomal segments resulting from complete or segmental chromosomal homozygosity, which may be indicative of uniparental disomy (UPD), consanguinity, as well as replicative DNA repair events, however also are common findings in normal populations. Knowing common LCSH of a population, which probably represent ancestral haplotypes of low-recombination regions in the genome, facilitates the interpretation of LCSH found in patients, allowing to prioritize those with possible clinical significance. However, population records of ancestral haplotype derived LCSH by SNP arrays are still scarce, particularly for countries such as Brazil where even for the clinic, microarrays that include SNPs are difficult to request due to their high cost. METHODS: In this study, we evaluate the frequencies and implications of LCSH detected by Affymetrix CytoScan® HD or 750 K platforms in 430 patients with neurodevelopmental disorders in southern Brazil. LCSH were analyzed in the context of pathogenic significance and also explored to identify ancestral haplotype derived LCSH. The criteria for considering a region as LCSH was homozygosis ≥3 Mbp on an autosome. RESULTS: In 95% of the patients, at least one LCSH was detected, a total of 1478 LCSH in 407 patients. In 2.6%, the findings were suggestive of UPD. For about 8.5% LCSH suggest offspring from first to fifth grade, more likely to have a clinical impact. Considering recurrent LCSH found at a frequency of 5% or more, we outline 11 regions as potentially representing ancestral haplotypes in our population. The region most involved with homozygosity was 16p11.2p11.1 (49%), followed by 1q21.2q21.3 (21%), 11p11.2p11.12 (19%), 3p21.31p21.2 (16%), 15q15 1q33p32.3 (12%), 2q11.1q12.1 (9%), 1p33p32.3 (6%), 20q11.21q11.23 (6%), 10q22.1q23.31 (5%), 6p22.2p22 (5%), and 7q11.22q11.23 (5%). CONCLUSIONS: In this work, we show the importance and usefulness of interpreting LCSH in the results of CMA wich incorporate SNPs.

Copy Number Variations in a Cohort of 420 Individuals with Neurodevelopmental Disorders From the South of Brazil.

Chromosomal microarray (CMA) is now recommended as first tier for the evaluation in individuals with unexplained neurodevelopmental disorders (ND). However, in developing countries such as Brazil, classical cytogenetic tests are still the most used in clinical practice, as reflected by the scarcity of publications of microarray investigation in larger cohorts. This is a retrospective study which analyses the reading files of CMA and available clinical data from 420 patients from the south of Brazil, mostly children, with neurodevelopmental disorders requested by medical geneticists and neurologists for diagnostic purpose. Previous karyotyping was reported for 138 and includes 17 with abnormal results. The platforms used for CMA were CYTOSCAN 750K (75%) and CYTOSCAN HD (25%). The sex ratio of the patients was 1.625 males :1 female and the mean age was 9.5 years. A total of 96 pathogenic copy number variations (CNVs), 58 deletions and 38 duplications, were found in 18% of the patients and in all chromosomes, except chromosome 11. For 12% of the patients only variants of uncertain clinical significance were found. No clinically relevant CNV was found in 70%. The main referrals for chromosomal microarrays (CMA) were developmental delay (DD), intellectual disability (ID), facial dysmorphism and autism spectrum disorder (ASD). DD/ID were present in 80%, facial dysmorphism in 52% and ASD in 32%. Some phenotypes in this population could be predictive of a higher probability to carry a pathogenic CNV, as follows: dysmorphic facial features (p-value = < 0.0001, OR = 0.32), obesity (p-value = 0.006, OR = 0.20), short stature (p-value = 0.032, OR = 0.44), genitourinary anomalies (p-value = 0.032, OR = 0.63) and ASD (p-value = 0.039, OR = 1.94). The diagnostic rate for CMA in this study was 18%. We present the largest report of CMA data in a cohort with ND in Brazil. We characterize the rare CNVs found together with the main phenotypes presented by each patient, list phenotypes which could predict a higher diagnostic probability by CMA in patients with a neurodevelopmental disorder and show how CMA and classical karyotyping results are complementary.

Recent Advances in Treatment Approaches of Mucopolysaccharidosis VI.

Mucopolysaccharidosis VI is caused by accumulation of the glycosaminoglycan dermatan sulfate in all tissues due to decreased activity of the enzyme arylsulfatase B. Patients exhibit multisystemic signs and symptoms in a chronic and progressive manner, especially with changes in the skeleton, cardiopulmonary system, cornea, skin, liver, spleen and meninges. Patients usually have normal intelligence. In the past, treatment of mucopolysaccharidoses was limited to palliative medical care. The outcome for affected patients improved with the introduction of new technologies as hematopoietic stem cell transplantation, relegated to specific situations after enzyme replacement therapy (ERT) became available. The specific ERT for MPS VI, galsulfase (Naglazyme®, Biomarin Pharmaceutical) was approved in 2005 by FDA and in 2006 by EMEA, and three clinical studies including 56 patients have evaluated the efficacy and safety. Long-term follow up data with patients treated up to 5 years showed that ERT is well tolerated and associated with sustained improvements in the patients' clinical condition. Intrathecal ERT may be considered in situations of high neurosurgical risk but still it is experimental in humans, as is intra-articular ERT. It is possible that the full impact of this therapy will only be demonstrated when patients are identified and treated soon after birth, as it was shown that early introduction of ERT produced immune tolerance and improved enzyme effectiveness in the cat model. New insights on the pathophysiology of MPS disorders are leading to alternative therapeutic approaches, as gene therapy, inflammatory response modulators and substrate reduction therapy.

Orthopedic manifestations in patients with mucopolysaccharidosis type II (Hunter syndrome) enrolled in the Hunter Outcome Survey.

Mucopolysaccharidosis type II (MPS II or Hunter syndrome) is a rare, inherited disorder caused by deficiency of the lysosomal enzyme iduronate-2-sulfatase. As a result of this deficiency, glycosaminoglycans accumulate in lysosomes in many tissues, leading to progressive multisystemic disease. The cardiopulmonary and neurological problems associated with MPS II have received considerable attention. Orthopedic manifestations are common but not as well characterized. This study aimed to characterize the prevalence and severity of orthopedic manifestations of MPS II and to determine the relationship of these signs and symptoms with cardiovascular, pulmonary and central nervous system involvement.Orthopedic manifestations of MPS II were studied using cross-sectional data from the Hunter Outcome Survey (HOS). The HOS is a global, physician-led, multicenter observational database that collects information on the natural history of MPS II and the long-term safety and effectiveness of enzyme replacement therapy.As of January 2009, the HOS contained baseline data on joint range of motion in 124 males with MPS II. In total, 79% of patients had skeletal manifestations (median onset, 3.5 years) and 25% had abnormal gait (median onset, 5.4 years). Joint range of motion was restricted for all joints assessed (elbow, shoulder, hip, knee and ankle). Extension was the most severely affected movement: the exception to this was the shoulder. Surgery for orthopedic problems was rare. The presence of orthopedic manifestations was associated with the presence of central nervous system and pulmonary involvement, but not so clearly with cardiovascular involvement.Orthopedic interventions should be considered on an individual-patient basis. Although some orthopedic manifestations associated with MPS II may be managed routinely, a good knowledge of other concurrent organ system involvement is essential. A multidisciplinary approach is required.

[Enzyme replacement therapy for mucopolysaccharidoses I, II and VI: recommendations from a group of Brazilian F experts]. / 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 80's treatment of MPS with bone marrow transplantation/hematopoietic stem cells transplantation (BMT/HSCT) was proposed and in the 90's, 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.

Mucopolysaccharidosis I, II, and VI: Brief review and guidelines for treatment.

Mucopolysaccharidoses (MPS) are rare genetic diseases caused by the deficiency of one of the lysosomal enzymes involved in the glycosaminoglycan (GAG) breakdown pathway. This metabolic block leads to the accumulation of GAG in various organs and tissues of the affected patients, resulting in a multisystemic clinical picture, sometimes including cognitive impairment. Until the beginning of the XXI century, treatment was mainly supportive. Bone marrow transplantation improved the natural course of the disease in some types of MPS, but the morbidity and mortality restricted its use to selected cases. The identification of the genes involved, the new molecular biology tools and the availability of animal models made it possible to develop specific enzyme replacement therapies (ERT) for these diseases. At present, a great number of Brazilian medical centers from all regions of the country have experience with ERT for MPS I, II, and VI, acquired not only through patient treatment but also in clinical trials. Taking the three types of MPS together, over 200 patients have been treated with ERT in our country. This document summarizes the experience of the professionals involved, along with the data available in the international literature, bringing together and harmonizing the information available on the management of these severe and progressive diseases, thus disclosing new prospects for Brazilian patients affected by these conditions.

Poland syndrome associated with an aberrant subclavian artery and vascular abnormalities of the retina in a child exposed to misoprostol during pregnancy.

BACKGROUND: Poland syndrome has been attributed to a process of vascular disruption, and exposure to misoprostol at 6-8 weeks of gestation has been shown to produce defects attributed to vascular disruption. Herein we report the first case of a patient with Poland syndrome associated with an aberrant subclavian artery and vascular abnormalities of the retina, whose mother used misoprostol during pregnancy. CASE: A White boy of 1 year and 7 months of age, whose mother used misoprostol during the second month of pregnancy, presented with bilateral epicanthal folds, aplasia of the sternocostal head of the pectoralis major muscle with a hypoplastic nipple on the right side, and asymmetry between the upper limbs. The results of an angiotomographic study showed the presence of an aberrant right subclavian artery. Ultrasonographic evaluation showed turbulence and a high peak in the diastolic velocity in both carotid arteries, suggesting stenosis. Ophthalmologic assessment disclosed an intense bilateral tortuosity of the retinal blood vessels, with arterialnarrowing and rarefaction of the retinal pigment epithelium. CONCLUSIONS: This case suggests that the mechanism of vascular disruption of misoprostol could be related to the aberrant subclavian artery and the observed Poland syndrome. His retinal findings are different from those in cases described thus far in the literature, and this pattern of anomaly has never been associated with a gestational exposure to misoprostol. The possibility of a relationship of the aberrant right subclavian artery and the pattern of blood flow verified in the carotid arteries with the eye fundus abnormalities could be causally related or simply coincidental.

Combined chemotherapy and teratogenicity.

BACKGROUND: The concomitant occurrence of breast cancer and pregnancy is relatively uncommon. We report the case of a patient with syndactyly, cleft hands, and absence of distal finger phalanges associated with maternal exposure to chemotherapeutic agents during the first trimester of pregnancy. These associations have not been previously described. CASE: The patient was born by normal delivery after 38 weeks of pregnancy. His mother became pregnant while receiving chemotherapy (cyclophosphamide, 5-fluorouracil, and adriamycin) for breast cancer, and the fetus was exposed to these drugs from conception to the 16th week of pregnancy. At birth, anomalies were observed, including a high-arched palate, microcephaly, a flat nasal bridge, bilateral syndactyly in the first and second fingers with a hand cleft between the second and third fingers and hypoplasia of the fifth fingers, and dystrophic nail of the fourth finger of the left hand. The patient's growth and development were deficient. CONCLUSIONS: The malformations associated with in utero exposure to these chemotherapeutic agents are highly variable, but growth deficiency and anomalies of the craniofacial region and limbs are the most common. The pattern of malformations in children who were congenitally exposed to chemotherapeutic agents appears to be directly related to the age at and duration of exposure, rather than to the specific drug itself. Effective contraception is essential for the safe use of a potential teratogen in nonpregnant women of reproductive age.

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

As mucopolissacaridoses (MPS) são doenças genéticas raras causadas pela deficiência de enzimas lisossômicas específicas que afetam o catabolismo de glicosaminoglicanos (GAG). O acúmulo de GAG em vários órgãos e tecidos nos pacientes afetados pelas MPS resulta em uma série de sinais e sintomas, integrantes de um quadro clínico multissistêmico que compromete ossos e articulações, vias respiratórias, sistema cardiovascular e muitos outros órgãos e tecidos, incluindo, em alguns casos, as funções cognitivas. Já foram identificados 11 defeitos enzimáticos que causam sete tipos diferentes de MPS. Antes do advento de terapias dirigidas para a restauração da atividade da enzima deficiente, o tratamento das MPS tinha como principal foco a prevenção e o cuidado das complicações, aspecto ainda bastante importante no manejo desses pacientes. Na década de 80 foi proposto o tratamento das MPS com transplante de medula óssea/transplante de células tronco hematopoiéticas (TMO/TCTH) e na década de 90 começou o desenvolvimento da Terapia de Reposição Enzimática (TRE), que se tornou uma realidade aprovada para uso clínico nas MPS I, II e VI na primeira década do século 21. Os autores deste trabalho têm a convicção de que um melhor futuro para os pacientes afetados pelas MPS depende da identificação, compreensão e manejo adequado das manifestações multissistêmicas dessas doenças, incluindo medidas de suporte (que devem fazer parte da assistência multidisciplinar regular destes pacientes) e terapias específicas. Embora a inibição da síntese de GAG e o resgate da atividade enzimática com moléculas pequenas também possam vir a ter um papel no manejo das MPS, o grande avanço disponível no momento é a TRE intravenosa. A TRE permitiu modificar radicalmente o panorama do tratamento das mucopolissacaridoses I, II e VI na última década, sendo que ainda pode estender seus benefícios em breve para a MPS IV A (cuja TRE já está em desenvolvimento clínico), com perspectivas para o tratamento da MPS III A e do déficit cognitivo na MPS II através de administração da enzima diretamente no sistema nervoso central (SNC). Um grande número de centros brasileiros, incluindo serviços de todas as regiões do país, já têm experiência com TRE para MPS I, II e VI. Essa experiência foi adquirida não só com o tratamento de pacientes como também com a participação de alguns grupos em ensaios clínicos envolvendo TRE para essas condições. Somados os três tipos de MPS, mais de 250 pacientes já foram tratados com TRE em nosso país. A experiência dos profissionais brasileiros, somada aos dados disponíveis na literatura internacional, permitiu elaborar este documento, produzido com o objetivo de reunir e harmonizar as informações disponíveis sobre o tratamento destas doenças graves e progressivas, mas que, felizmente, são hoje tratáveis, uma realidade que traz novas perspectivas para os pacientes brasileiros afetados por essas condições.

Terapia de reposição enzimática para as mucopolissacaridoses I, II e VI: recomendações de um grupo de especialistas brasileiros / Enzyme replacement therapy for mucopolysaccharidoses I, II and VI: recommendations from a group of Brazilian F experts

As mucopolissacaridoses (MPS) são doenças genéticas raras causadas pela deficiência de enzimas lisossômicas específicas que afetam o catabolismo de glicosaminoglicanos (GAG). O acúmulo de GAG em vários órgãos e tecidos nos pacientes afetados pelas MPS resulta em uma série de sinais e sintomas, integrantes de um quadro clínico multissistêmico que compromete ossos e articulações, vias respiratórias, sistema cardiovascular e muitos outros órgãos e tecidos, incluindo, em alguns casos, as funções cognitivas. Já foram identificados 11 defeitos enzimáticos que causam sete tipos diferentes de MPS. Antes do advento de terapias dirigidas para a restauração da atividade da enzima deficiente, o tratamento das MPS tinha como principal foco a prevenção e o cuidado das complicações, aspecto ainda bastante importante no manejo desses pacientes. Na década de 80 foi proposto o tratamento das MPS com transplante de medula óssea/transplante de células tronco hematopoiéticas (TMO/TCTH) e na década de 90 começou o desenvolvimento da Terapia de Reposição Enzimática (TRE), que se tornou uma realidade aprovada para uso clínico nas MPS I, II e VI na primeira década do século 21. Os autores deste trabalho têm a convicção de que um melhor futuro para os pacientes afetados pelas MPS depende da identificação, compreensão e manejo adequado das manifestações multissistêmicas dessas doenças, incluindo medidas de suporte (que devem fazer parte da assistência multidisciplinar regular destes pacientes) e terapias específicas...

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 primnarily on prevention and care of complications, still a very important aspect in the management of these patients. In the 80's treatment of MPS with bone marrow transplantation/hematopoietic stem cells transplantation (BMT/HSCT) was proposed and in the 90's, 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...