Consideraciones bucodentales en pacientes con Síndrome de Morquio / Dental considerations of the morquio síndrome

La mucopolisacaridosis tipo IV (MPS-IV) también conocida como enfermedad de Morquio en recuerdo del pediatra uruguayo Luis Morquio que la describió por primera vez, es una enfermedad congénita causada por la deficiencia de la enzima N-acetilgalactosamina 6 sulfatasa o de la enzima B-Galactosidasa. Estas anomalías enzimáticas tienen como consecuencia que se acumulen en diferentes tejidos del organismo cantidades elevadas de mucopolisacaridos. En la bibliografía se describe con detalle los defectos del esmalte que presentan los pacientes diagnosticados del síndrome de Morquio. Estos defectos son una característica aparentemente constante en la enfermedad y, por lo tanto, hace necesaria las visitas al odontólogo para su control evitándose problemas mayores. Dichos defectos consisten en un esmalte anormalmente delgado, que es áspero debido a los numerosos hoyos diminutos y a una superficie irregular. La delgadez del esmalte da como resultado una forma alterada y decoloración de los dientes que, añadido a los diastemas interdentales, provocan alteraciones en la oclusión. Aparte de estos defectos, el esmalte es histológicamente normal y tiene una du-reza y radiodensidad normales. El trata-miento odontológico de los pacientes con MPS-IV requiere colaboración multidisciplinar, debido a que las manifestaciones orales de la enfermedad pueden aparecer a cualquier edad, resultando en ocasiones tedioso para el paciente y complicado para el profesional. Especial mención merecen las terapias utilizadas como trata-miento sintomático de la enfermedad, así como el manejo de la vía aérea en el caso de intervenciones bajo anestesia general o sedación para tratar ciertas patologías del territorio bucomaxilodental

Mucopolysaccharidosis type IV (MPS-IV) also known as Morquio’s disease in memory of the Uruguayan pediatrician Luis Morquio who described it for the first time, is a congenital disease caused by the deficiency of the enzyme N-acetylgalactosamine 6 sulfatase or enzyme B -Galactosidase. These enzymatic anomalies result in high amounts of mucopolysaccharides accumulating in different tissues of the organism. The enamel defects presented by patients diagnosed with Morquio syndrome are described in detail in the bibliography. These defects are an apparently constant feature in the disease and, therefore, make visits to the dentist necessary for their control, avoiding major problems. These defects consist of an abnormally thin enamel that is rough due to numerous tiny holes and an irregular surface. The thinness of the enamel results in an altered form and discoloration of the teeth, which added to the interdental diastemas, cause alterations in the occlusion. Apart from these defects, the enamel is histologically normal and has a normal hardness and radiodensity.Dental treatment of patients with MPS-IV requires multidisciplinary collaboration, because the oral manifestations of the disease can appear at any age, being sometimes tedious for the patient and complicated for the professional. Special mention should be made of the therapies used as a symptomatic treatment of the disease, as well as the management of the airway in the case of interventions under general anesthesia or sedation to treat certain pathologies of the bucomaxillodental territory

Audiometric evaluation in individuals with mucopolysaccharidosis.

OBJECTIVES: To characterize the audiometric evaluation and acoustic immittance measures in different types of mucopolysaccharidosis. METHOD: Fifty-three mucopolysaccharidosis patients were evaluated. The classification consisted of type I (Hurler syndrome, Hurler-Scheie and Scheie syndrome), type II (Hunter syndrome), type III (Sanfilippo syndrome), type IV (Morquio syndrome), and type VI (Maroteaux-Lamy syndrome). Immittance audiometry and play or conventional threshold tone audiometry were used to obtain auditory thresholds and were chosen according to the patient's chronological age and ability to understand/respond to the procedure. The findings were analyzed using descriptive statistics and considering the recommendations for research involving human beings contained in Resolution CNE N° 466/2012. RESULTS: Fifty-one subjects (96.2%) had hearing loss, and the conductive type was the most frequent. Only two (3.8%) patients presented bilateral thresholds within normal limits, one with type IV mucopolysaccharidosis and the other with type VI. There were 11 individuals (20.8%) with mucopolysaccharidosis type I with mixed hearing loss, 9 (16.9%) individuals with type I with conductive hearing loss and 9 (16.9%) with type VI with conductive hearing loss. Mild hearing loss was most common (37.3%), followed by moderately severe hearing loss (36.3%). The type B tympanometric curve (80.4%) was the most frequent. CONCLUSIONS: Most of the individuals with mucopolysaccharidosis types I, II, III, IV and VI presented mixed or conductive hearing losses of mild to moderately severe degree, type B tympanograms and an absence of contralateral acoustic reflexes.

The relationships between urinary glycosaminoglycan levels and phenotypes of mucopolysaccharidoses.

BACKGROUND: The aim of this study was to use the liquid chromatography/tandem mass spectrometry (LC-MS/MS) method to quantitate levels of three urinary glycosaminoglycans (GAGs; dermatan sulfate [DS], heparan sulfate [HS], and keratan sulfate [KS]) to help make a correct diagnosis of mucopolysaccharidosis (MPS). METHODS: We analyzed the relationships between phenotypes and levels of urinary GAGs of 79 patients with different types of MPS. RESULTS: The patients with mental retardation (n = 21) had significantly higher levels of HS than those without mental retardation (n = 58; 328.8 vs. 3.2 µg/ml, p < 0.001). The DS levels in the patients with hernia, hepatosplenomegaly, claw hands, coarse face, valvular heart disease, and joint stiffness were higher than those without. Twenty patients received enzyme replacement therapy (ERT) for 1-12.3 years. After ERT, the KS level decreased by 90% in the patients with MPS IVA compared to a 31% decrease in the change of dimethylmethylene blue (DMB) ratio. The DS level decreased by 79% after ERT in the patients with MPS VI compared to a 66% decrease in the change of DMB ratio. CONCLUSIONS: The measurement of GAG fractionation biomarkers using the LC-MS/MS method is a more sensitive and reliable tool than the DMB ratio for MPS high-risk screening, diagnosis, subclass identification, and monitoring the efficacy of ERT.

Clinical presentation and diagnosis of mucopolysaccharidoses.

Mucopolysaccharidoses (MPS) are estimated to affect1 in 25,000 live births although specific rates vary between the ethnic origin and country. MPS are a group of lysosomal storage disorders, which cause the buildup of GAG(s) due to insufficient or absent GAG-degrading enzymes. With seven types of MPS disorders and eleven subtypes, the MPS family presents unique challenges for early clinical diagnosis due to the molecular and clinical heterogeneity between groups and patients. Novel methods of early identification, particularly newborn screening through mass spectrometry, can change the flow of diagnosis, allowing enzyme and GAG quantification before the presentation of clinical symptoms improving outcomes. Genetic testing of patients and their families can also be conducted preemptively. This testing enables families to make informed decisions about family planning, leading to prenatal diagnosis. In this review, we discuss the clinical symptoms of each MPS type as they initially appear in patients, biochemical and molecular diagnostic methods, and the future of newborn screening for this group of disorders.

Glycosaminoglycans analysis in blood and urine of patients with mucopolysaccharidosis.

To explore the correlation between glycosaminoglycan (GAG) levels and mucopolysaccharidosis (MPS) type, we have evaluated the GAG levels in blood of MPS II, III, IVA, and IVB and urine of MPS IVA, IVB, and VI by tandem mass spectrometry. Dermatan sulfate (DS), heparan sulfate (HS), keratan sulfate (KS; mono-sulfated KS, di-sulfated KS), and the ratio of di-sulfated KS in total KS were measured. Patients with untreated MPS II had higher levels of DS and HS in blood while untreated MPS III had higher levels of HS in blood than age-matched controls. Untreated MPS IVA had higher levels of KS in blood and urine than age-matched controls. The ratio of blood di-sulfated KS/total KS in untreated MPS IVA was constant and higher than that in controls for children up to 10 years of age. The ratio of urine di-sulfated KS/total KS in untreated MPS IVA was also higher than that in age-matched controls, but the ratio in untreated MPS IVB was lower than controls. ERT reduced blood DS and HS in MPS II, and urine KS in MPS IVA patients, although GAGs levels remained higher than the observed in age-matched controls. ERT did not change blood KS levels in MPS IVA. MPS VI under ERT still had an elevation of urine DS level compared to age-matched controls. There was a positive correlation between blood and urine KS in untreated MPS IVA patients but not in MPS IVA patients treated with ERT. Blood and urine KS levels were secondarily elevated in MPS II and VI, respectively. Overall, measurement of GAG levels in blood and urine is useful for diagnosis of MPS, while urine KS is not a useful biomarker for monitoring therapeutic efficacy in MPS IVA.

Growth impairment in mucopolysaccharidoses.

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders that affect regulation of glycosaminoglycan (GAG) processing. In MPS, the lysosomes cannot efficiently break down GAGs, and the specific GAGs accumulated depend on the type of MPS. The level of impairment of breakdown varies between patients, making this one of the many factors that lead to a range of clinical presentations even in the same type of MPS. These clinical presentations usually involve skeletal dysplasia, in which the most common feature is bone growth impairment and successive short stature. Growth impairment occurs due to the deposition and retention of GAGs in bone and cartilage. The accumulation of GAGs in these tissues leads to progressive damage in cartilage that in turn reduces bone growth by destruction of the growth plate, incomplete ossification, and imbalance of growth. Imbalance of growth leads to various skeletal abnormalities including disproportionate dwarfism with short neck and trunk, prominent forehead, rigidity of joints, tracheal obstruction, kyphoscoliosis, pectus carinatum, platyspondyly, round-shaped vertebral bodies or beaking sign, underdeveloped acetabula, wide flared iliac, coxa valgus, flattered capital femoral epiphyses, and genu valgum. If left untreated, skeletal abnormalities including growth impairment result in a significant impact on these patients' quality of life and activity of daily living, leading to high morbidity and severe handicap. This review focuses on growth impairment in untreated patients with MPS. We comprehensively describe the growth abnormalities through height, weight, growth velocity, and BMI in each type of MPS and compare the status of growth with healthy age-matched controls. The timing, the degree, and the difference in growth impairment of each MPS are highlighted to understand the natural course of growth and to evaluate future therapeutic efficacy.

Audiometric evaluation in individuals with mucopolysaccharidosis

OBJECTIVES: To characterize the audiometric evaluation and acoustic immittance measures in different types of mucopolysaccharidosis. METHOD: Fifty-three mucopolysaccharidosis patients were evaluated. The classification consisted of type I (Hurler syndrome, Hurler-Scheie and Scheie syndrome), type II (Hunter syndrome), type III (Sanfilippo syndrome), type IV (Morquio syndrome), and type VI (Maroteaux-Lamy syndrome). Immittance audiometry and play or conventional threshold tone audiometry were used to obtain auditory thresholds and were chosen according to the patient's chronological age and ability to understand/respond to the procedure. The findings were analyzed using descriptive statistics and considering the recommendations for research involving human beings contained in Resolution CNE N° 466/2012. RESULTS: Fifty-one subjects (96.2%) had hearing loss, and the conductive type was the most frequent. Only two (3.8%) patients presented bilateral thresholds within normal limits, one with type IV mucopolysaccharidosis and the other with type VI. There were 11 individuals (20.8%) with mucopolysaccharidosis type I with mixed hearing loss, 9 (16.9%) individuals with type I with conductive hearing loss and 9 (16.9%) with type VI with conductive hearing loss. Mild hearing loss was most common (37.3%), followed by moderately severe hearing loss (36.3%). The type B tympanometric curve (80.4%) was the most frequent. CONCLUSIONS: Most of the individuals with mucopolysaccharidosis types I, II, III, IV and VI presented mixed or conductive hearing losses of mild to moderately severe degree, type B tympanograms and an absence of contralateral acoustic reflexes.

Epidemiology of mucopolysaccharidoses.

The aim of this study was to obtain data about the epidemiology of the different types of mucopolysaccharidoses in Japan and Switzerland and to compare with similar data from other countries. Data for Japan was collected between 1982 and 2009, and 467 cases with MPS were identified. The combined birth prevalence was 1.53 per 100,000 live births. The highest birth prevalence was 0.84 for MPS II, accounting for 55% of all MPS. MPS I, III, and IV accounted for 15, 16, and 10%, respectively. MPS VI and VII were more rare and accounted for 1.7 and 1.3%, respectively. A retrospective epidemiological data collection was performed in Switzerland between 1975 and 2008 (34years), and 41 living MPS patients were identified. The combined birth prevalence was 1.56 per 100,000 live births. The highest birth prevalence was 0.46 for MPS II, accounting for 29% of all MPS. MPS I, III, and IV accounted for 12, 24, and 24%, respectively. As seen in the Japanese population, MPS VI and VII were more rare and accounted for 7.3 and 2.4%, respectively. The high birth prevalence of MPS II in Japan was comparable to that seen in other East Asian countries where this MPS accounted for approximately 50% of all forms of MPS. Birth prevalence was also similar in some European countries (Germany, Northern Ireland, Portugal and the Netherlands) although the prevalence of other forms of MPS is also reported to be higher in these countries. Birth prevalence of MPS II in Switzerland and other European countries is comparatively lower. The birth prevalence of MPS III and IV in Switzerland is higher than in Japan but comparable to that in most other European countries. Moreover, the birth prevalence of MPS VI and VII was very low in both, Switzerland and Japan. Overall, the frequency of MPS varies for each population due to differences in ethnic backgrounds and/or founder effects that affect the birth prevalence of each type of MPS, as seen for other rare genetic diseases. Methods for identification of MPS patients are not uniform across all countries, and consequently, if patients are not identified, recorded prevalence rates will be aberrantly low.

The utility of two dimensional electrophoresis in diagnosis of mucopolysaccharidosis disorders.

BACKGROUND: Mucopolysaccharidoses are a group of inherited lysosomal storage disorders consisting of 7 distinct clinical types and numerous subtypes. These are the result of deficiency of certain lysosomal degradative enzymes which are required to breakdown Glycosaminoglycans. The clinical features observed among Mucopolysaccharidoses subtypes show overlapping signs and symptoms with other lysosomal storage disorders and rheumatologic disorders. This makes clinical diagnosis a challenge. With the advent of new therapies, appropriate medical management is possible and hence establishing timely diagnosis has become crucial. METHODS: In this retrospective data analysis, 2 different diagnostic approaches were discussed. The first diagnostic approach involves screening by Glycosaminoglycans' quantification and two-dimensional cellulose acetate electrophoresis and confirmation by enzyme analysis. The second diagnostic approach involves direct enzyme analysis on basis of the clinical suspicion. RESULTS: This first approach seems to be appropriate for the diagnosis of almost all types of Mucopolysaccharidoses. The second approach is found to be more pertinent for type III Mucopolysaccharidosis. CONCLUSIONS: Our retrospective data analysis suggests that urinary Glycosaminoglycans screening followed by enzyme analysis confirmation seems to be rapid and cost effective approach for diagnosing these disorders.

Alterations of mucosa of the larynx and hypopharynx in patients with mucopolysaccharidoses.

OBJECTIVE: This study aimed to: assess the mucosal alterations of the larynx and hypopharynx typical for mucopolysaccharidoses, in a standardised manner; compare the severity in different subtypes of mucopolysaccharidoses; and monitor the effect of an enzyme replacement therapy. METHODS: A classification for mucosal alterations of the larynx and hypopharynx was developed and utilised in 55 patients with mucopolysaccharidoses. Fifteen patients who started treatment with enzyme replacement therapy were followed longitudinally. RESULTS: The most severe alterations were seen in the posterior region of the larynx and the arytenoids, and in the region of the false vocal folds. The alterations were most severe in patients with mucopolysaccharidosis II. No clear trend was observed in the patients who received enzyme replacement therapy. CONCLUSION: Quantification of mucosal alterations of the hypopharynx and larynx in mucopolysaccharidoses patients can provide information about the disease's natural process and about the efficacy of enzyme replacement therapy.

Fluorimetric assays for N-acetylgalactosamine-6-sulfatase and arylsulfatase B based on the natural substrates for confirmation of mucopolysaccharidoses types IVA and VI.

BACKGROUND: Treatments have been developed for mucopolysaccharidoses IVA (MPS IVA) and MPS VI suggesting the need for eventual newborn screening. Biochemical enzyme assays are important for diagnosis. Previously reported fluorimetric assays of the relevant enzymes are based on substrates with poor activity or specificity. METHODS: We developed new fluorimetric assays for N-acetylgalactosamine-6-sulfatase (GALNS) and arylsulfatase B (ARSB) based on the natural substrates, N-acetylgalactosamine-6-sulfate (and 4-sulfate), which have improved activity and specificity toward the relevant enzymes. The new substrates were tested on dried blood spots on newborn screening cards, and assays showed acceptable linearity in response with the amount of enzyme present (using quality control samples). RESULTS: When tested on dried blood spots from random newborns and affected patients, the assays showed good discrimination between the 2 sample groups. CONCLUSIONS: The analytical range of the new fluorimetric assays, defined as the ratio of enzyme-dependent-to-enzyme-independent assay response, is likely to be insufficient to use these assays for newborn screening. Rather, these new fluorimetric assays should be useful in a diagnostic lab to confirm a diagnosis via biochemical enzyme testing.

Prevalence rates of mucopolysaccharidoses in Poland.

The aim of this study was to determine the prevalence rates of mucopolysaccharidoses in Poland and to compare them with other European countries. A retrospective epidemiological survey covering the period between 1970 and 2010 was implemented. Multiple ascertainment sources were used to identify affected patients. The overall prevalence of mucopolysaccharidoses in the Polish population was 1.81 per 100,000. Five different mucopolysaccharidoses were diagnosed in a total of 392 individuals. MPS III was the most frequent mucopolysaccharidosis, with a birth prevalence of 0.86 per 100,000 live births. A prevalence of approximately 0.22 cases per 100,000 births was obtained for MPS I. For MPS II, the prevalence was estimated as 0.45 cases per 100,000 births; for MPS IV A and B as 0.14 cases in 100,000 births; and that for MPS VI as 0.03 cases per 100,000 births. 1. The prevalence pattern of mucopolysaccharidosis in Poland is lower when compared to the prevalence reported for other European countries, such as the Netherlands, Czech Republic, or Germany, but similar to countries like Sweden and Denmark. 2. Different frequencies of the various forms of mucopolysaccharidosis were observed. 3. In the case of MPS VI, the incidence values for Poland were the lowest of all the studies previously published so far.

Improved reagents for newborn screening of mucopolysaccharidosis types I, II, and VI by tandem mass spectrometry.

Tandem mass spectrometry for the multiplex and quantitative analysis of enzyme activities in dried blood spots on newborn screening cards has emerged as a powerful technique for early assessment of lysosomal storage diseases. Here we report the design and process-scale synthesis of substrates for the enzymes α-l-iduronidase, iduronate-2-sulfatase, and N-acetylgalactosamine-4-sulfatase that are used for newborn screening of mucopolysaccharidosis types I, II, and VI. The products contain a bisamide unit that is hypothesized to readily protonate in the gas phase, which improves detection sensitivity by tandem mass spectrometry. The products contain a benzoyl group, which provides a useful site for inexpensive deuteration, thus facilitating the preparation of internal standards for the accurate quantification of enzymatic products. Finally, the reagents are designed with ease of synthesis in mind, thus permitting scale-up preparation to support worldwide newborn screening of lysosomal storage diseases. The new reagents provide the most sensitive assay for the three lysosomal enzymes reported to date as shown by their performance in reactions using dried blood spots as the enzyme source. Also, the ratio of assay signal to that measured in the absence of blood (background) is superior to all previously reported mucopolysaccharidosis types I, II, and VI assays.

Current and potential therapeutic strategies for mucopolysaccharidoses.

WHAT IS KNOWN AND OBJECTIVE: Mucopolysaccharidoses (MPSs) are a group of rare inherited metabolic diseases caused by genetic defects in the production of lysosomal enzymes. MPSs are clinically heterogeneous and are characterized by progressive deterioration in visceral, skeletal and neurological functions. This article aims to review the classification and pathophysiology of MPSs and discuss current therapies and new targeted agents under development. METHODS: A Medline search through PubMed was performed for relevant articles and treatment guidelines on MPSs published in English for years 1970 to September of 2013 inclusive. The references listed in the identified articles, prescribing information of the drugs approved for the treatment of MPSs, as well as recent clinical trial information posted on Clinicaltrials.gov website, were reviewed. RESULTS AND DISCUSSION: Until recently, supportive care was the only option available for the management of MPSs. In the early 2000s, enzyme replacement therapy (ERT) was approved by the United States Food and Drug Administration (FDA) for the treatment of MPS I, II and VI. Clinical trials of ERT showed substantial improvements in patients' somatic symptoms; however, no benefit was found in the neurological symptoms because the enzymes do not readily cross the blood-brain barrier (BBB). Haematopoietic stem cell transplantation (HSCT), another potentially curative treatment, is not routinely advocated in clinical practice due to its high risk profile and lack of evidence for efficacy, except in preserving cognition and prolonging survival in young patients with severe MPS I. In recent years, substrate reduction therapy (SRT) and gene therapy have been rapidly gaining greater recognition as potential therapeutic avenues. WHAT IS NEW AND CONCLUSION: Enzyme replacement therapy (ERT) is effective for the treatment of many somatic symptoms, particularly walking ability and respiratory function, and remains the mainstay of MPS treatment. The usefulness of HSCT has not been established adequately for most MPSs. Although still under investigation, SRT and gene therapy are promising MPS treatments that may prevent the neurodegeneration not affected by ERT.

Measuring corneal clouding in patients suffering from mucopolysaccharidosis with the Pentacam densitometry programme.

AIM: To identify a means to objectively measure corneal clouding in patients with mucopolysaccharidosis in a prospective controlled clinical trial. METHODS: Corneal haze was assessed by slit lamp examination and measured using the densitometry programme of the Pentacam, a rotating Scheimpflug camera in 33 mucopolysaccharidoses (MPS) patients and 32 controls. RESULTS: Pentacam measurements were available in 31 right and 31 left eyes of 32 patients and in 32 left and right eyes of 32 subjects in the control group. Slit lamp findings correlated very well with corneal density measurements (Spearman correlation right eye (OD)/left eye (OS)=0.782/0.791). MPS patients had higher density units (median OD/OS=14.1/14.7) than control subjects (median OD/OS=6.7/6.9, p<0.001). In patients, the corneal centre density values (median OD/OS=13.8/14.0) did not differ from corneal periphery values (median OD/OS=14.3/14.7). CONCLUSIONS: The densitometry programme of the Pentacam provides objective measurement of corneal haze in mucopolysaccharidosis patients.

Mucopolysaccharide disorders in orthopaedic surgery.

The mucopolysaccharidoses (MPSs) are a family of disorders characterized by the accumulation of glycosaminoglycans, which is caused by enzyme deficiencies in the lysosomal metabolism of these normal cellular byproducts. Skeletal abnormalities are early and prominent features of MPS, and the orthopaedic surgeon is often the first healthcare provider to raise suspicion for this diagnosis. Recently developed medical therapies for the management of MPS (ie, hematopoietic stem cell transplantation, intravenous enzyme replacement therapy) have led to increased lifespan but have not had much effect on the development of skeletal deformities. Patients must be monitored carefully and treated surgically as necessary. Conditions that may require surgical management include cervical spine and atlantoaxial instability, gibbus deformity, hip dysplasia and osteonecrosis, genu valgum, and carpal tunnel syndrome. The orthopaedic surgeon should have a basic understanding of MPS and of the clinical presentation, musculoskeletal abnormalities, and radiographic findings associated with this group of disorders.

Compromiso respiratorio en mucopolisacaridosis / Respiratory manifestations in mucopolysaccharidosis

Mucopolysaccharidosis (MPS) are part of the so-called lysosomal diseases, in which the deposit of different glycosaminoglycans, depending on the enzyme deficit, generates multi-systemic manifestations, being the respiratory system one of the most affected and associated with significant morbidity and mortality. Different types of MPS show a variable degree of organ compromise even from the early stages of life: obstruction of the upper airway of varying degree, persistent rhinorrhea, otitis media, obstructive pathology of the peripheral airway, pneumonias or other infections associated with a poor mucociliary drainage are the main manifestations presented by patients. The compromise of the neurological and musculoskeletal system also brings the compromise of the respiratory pump. From that perspective the approach must be multidisciplinary, since there are several organs and systems involved. Current therapy is directed to replace the deficient enzyme but it’s available only for some of them, which delays the progression of the disease but does not stop it, even more so there is no effect on the central nervous system, being the cognitive compromise inevitable. Bone marrow transplant is a therapy not exempt of complications, but capable of changing the progression of the disease in its early stages. Therapeutic approach is based on support measures and treatment of concurrent complications, both of which will be discussed in the following article.

Las Mucopoliscaridosis (MPS) son parte de las denominadas enfermedades lisosomales. El depósito de los distintos glicosaminoglicanos comprometidos, dependiendo del déficit enzimático, genera manifestaciones multisistémicas, en donde el sistema respiratorio es uno de los principales afectados y que se asocia con morbilidad y mortalidad significativa. Los diferentes tipos de MPS presentan un grado variable de compromiso desde etapas precoces de la vida, síntomas de obstrucción de vía aérea superior de grado variable, rinorrea persistente, otitis media, patología obstructiva de vía aérea periférica, neumonías o infecciones asociadas a un mal drenaje mucociliar son las principales manifestaciones que los pacientes presentan. El compromiso neurológico y musculo esquelético, trae consigo además el compromiso de la bomba respiratoria. Desde esa perspectiva el enfoque debe ser multidisciplinario, ya que el compromiso abarca varios órganos y sistemas. Las actuales terapias están dirigidas a reemplazar la enzima deficitaria, disponibles sólo para algunas de ellas, esto trae consigo el retardo de la evolución de la enfermedad pero no lo evita, considerando que más aun no tiene ningún efecto sobre el sistema nervioso central, por lo que el compromiso cognitivo es inevitable. El trasplante de médula es una terapia no exenta de complicaciones, pero que es capaz de cambiar la progresión de la enfermedad en las etapas precoces de ella. El enfoque terapéutico se basa en terapia de sostén y el manejo de las distintas complicaciones que se van dando, siendo éstos los ejes del siguiente artículo.