Use of a commercial agarose gel for analysis of urinary glycosaminoglycans in mucopolysaccharidoses

ABSTRACT Mucopolysaccharidoses (MPS) are a group of inherited metabolic disorders caused by deficiency of enzymes that degrade glycosaminoglycans (GAGs). Urinary excretion of GAGs is a common feature of MPS, and is considered their major biomarker. We aimed to adapt the GAG electrophoresis method to a commercial agarose gel which would be able to separate urinary GAGs in a simpler way with good sensitivity and reproducibility. Urine samples from patients previously diagnosed with MPS I, IV, and VI were used as electrophoretic standards. Samples from patients on enzyme replacement therapy (ERT) were also assessed. Commercial agarose gel electrophoresis was effective, showing proper definition and separation of GAG bands. Detection sensitivity exceeded 0.1 µg and band reproducibility were consistent. GAG bands quantified in urine samples from patients on ERT correlated very strongly (correlation coefficient = 0.98) with total GAG concentrations. This application of gel electrophoresis demonstrates the possibility of monitoring patients with MPS treated with ERT by analyzing separately the GAGs excreted in urine. We suggest this process should be applied to MPS screening as well as to follow-up of patients on treatment.

Mucopolisacaridosis: características clínicas, diagnóstico y de manejo / Mucopolysaccharidosis: clinical features, diagnosis and management

Las mucopolisacaridosis (MPS) son un grupo de enfermedades raras (huérfanas), de baja prevalencia, caracterizadas por la deficiencia de enzimas que participan en el metabolismo de glucosaminglucanos (GAG) a nivel lisosomal. Se caracteriza por acumulación de GAG intracelular, produciendo alteraciones de múltiples órganos y sistemas. Su diagnóstico se basa en el conocimiento de las manifestaciones clínicas, realizar el análisis bioquímico para identificar el tipo de GAG que se está acumulando y confirmar el tipo de enfermedad con la determinación enzimática correspondiente. Su identificación es fundamental para iniciar un tratamiento oportuno, teniendo en cuenta que actualmente existe manejo transdisciplinario y tratamiento de reemplazo enzimático para MPS I (síndrome de Hurler), MPS II (síndrome de Hunter), MPS IV (síndrome de Morquio) y MPS VI (síndrome de Maroteaux-Lamy). En esta revisión se analizan cada uno de estos síndromes, su diagnóstico y tratamiento.

The mucopolysaccharidoses (MPS) are a group of rare (orphan) diseases, characterised by a deficiency of enzymes involved in the metabolism of glycosaminoglycans (GAGs) at lysosomal level. When there is a deficiency of a particular enzyme there is an accumulation of GAGs in the cells resulting in progressive cellular damage, which can affect multiple organ systems and lead to organ failure. Diagnosis is based on knowledge of the clinical manifestations, performing biochemical analyses to identify the type of GAG that is accumulating, and confirm the type of disorder with the corresponding enzymatic determination. Their identification is essential to initiate early treatment, taking into account that multidisciplinary management and enzyme replacement therapy is available for MPS I (Hurler syndrome), MPS II (Hunter syndrome), MPS IV (Morquio syndrome), and MPS VI (Maroteaux-Lamy syndrome. In this review, an analysis is made of each of these syndromes, as well as their diagnosis and treatment.

Mucopolisacaridosis (síndrome de Hunter) / Mucopolysaccharidosis (Hunter syndrome)

Se realiza una presentación de un caso interesante, no comúnmente visto en la práctica médica, de unos de los tipos de mucopolisacaridosis, específicamente de un síndrome de Hunter. Se hace esta presentación con el objetivo de dar a conocer a estudiantes y profesionales de la salud, mediante fotos, las características físicas del paciente con dicho sídrome, quien llegó desnutrido al hospital; se le operó de la hernia umbilical y se mejoró su estado nutricional al compensarse su hepatopatía. Se le da el alta médica en mejores condiciones(AU)

We present here an interesting case of mucopolysaccharidoses, which is not commonly seen in medical practice, specifically a Hunter syndrome. This presentation is done in order to make known to students and health professionals, through photos, the physical characteristics of the patient with such syndrome. This patient arrived malnourished at the hospital, he was operated on the umbilical hernia and improved his nutritional status by compensating for his liver disease. This patient had medical discharge in better conditions(AU)

Avaliação do comprometimento auditivo em pacientes com mucopolissacaridose / Evaluation of hearing loss in patients with mucopolysaccharides Psicol

Introdução: Mucopolissacaridose (MPS) é um conjunto de doenças raras causadas pela deficiência de enzimas lisossômicas levando ao acúmulo de glicosaminoglicanos (GAG) em órgãos e tecidos, responsáveis pelo quadro clínico multissistêmico, crônico e progressivo. O comprometimento auditivo é frequente. Objetivo: Avaliar manifestações auditivas de pacientes com MPS. Metodologia: Estudo descritivo, série de casos do comprometimento auditivo de pacientes com MPS. Foi realizada avaliação retrospectiva através de revisão de prontuário e avaliação prospectiva de dezembro de 2012 a outubro de 2014. Foram analisados a primeira e a última avaliação otorrinolaringológica (ORL) e audiológica realizada. Resultados: A principal queixa auditiva foi a hipoacusia. Aperdaauditiva estava presente em quase todos os pacientes, sendo que a perda auditiva condutiva foi a mais frequente, especialmente nos pacientes com MPS VI. Conclusão: A perda auditiva é muito frequente em pacientes com MPS, devendo o acompanhamento audiológico ser realizado precocemente.

Introduction: Mucopolysaccharidosis (MPS) is a set of rare diseases caused by deficiency of lysosomal enzymes leading to accumulation of glicosaminoglicanos (GAG) in tissues and organs responsible for the multisystemic clinical, chronic and progressive symptons. Objective: Todescribe the profile of otorhinolaryngological clinical examination and audiology tests of patients with MPS disease. Methods:Study of case series. The evaluation was performed, at the beginning, in 31 patients with MPS I, II, IIIA, IV and VI. Results: The most common hearing complaint was hearing loss and it was confirmed by audiology tests in almost 100% of patients, mostly with condutive hearing loss. Conclusions: It is important to evaluate the complaints, physical examination and audiology tests in MPS disease. Otorhinolaryngologist should be part of professional group that follow these patients in order to better monitor their hearing and provide early hearing rehabilitation.

Las mucopolisacaridosis / The mucopolysaccharidosis

Las mucopolisacaridosis (MPS) son errores innatos del metabolismo de los glicosaminoglicanos (GAG), que ocurren por déficit de alguna de las enzimas que degradan estas moléculas en los lisosomas. Esto conduce al depósito intralisosomal progresivo de GAG en diferentes tejidos, lo que explica el carácter multistémico de estas patologías. Las MPS, se presentan con una frecuencia aproximada de 1 caso en 10.000 a 25.000 recién nacidos vivos y son de herencia autosómica recesiva, salvo la MPS II o enfermedad de Hunter, que se hereda ligada al cromosoma X. Las características clínicas más frecuentes de las MPS son la presencia de rasgos faciales toscos, macrocefalia, opacidades corneales, disostosis múltiple, talla baja, valvulopatía mitroaórtica, hepatoesplenomegalia, hernias umbilical e inguinales, con o sin retraso del desarrollo sicomotor y con un deterioro neurológico progresivo. Salvo para las formas menos severas de MPS I, hasta ahora no hay un tratamiento efectivo para estas patologías, por lo que el daño sistémico progresivo produce la muerte entre los fines de la primera y de la cuarta década de la vida. En esta revisión se discuten las características clínicas de las MPS con las particularidades de cada fenotipo, el modo de confirmar el diagnóstico y los avances recientes en su tratamiento.

Diagnosis of mucopolysaccharidoses: how to avoid false positives and false negatives.

OBJECTIVE: This paper advocates a complete procedure, which includes both quantitative and qualitative analysis of urinary GAGs in the diagnosis of MPS in a clinically suspected population. METHODS: Urine samples from 219 clinically suspected mucopolysaccharidoses (MPS) patients and 91 controls were analysed using a combination of methods. Quantitation of isolated urinary glycosaminoglycans (GAGs) were carried out using acid alcian blue complex formation method and qualitative urinary GAG analysis by multisolvent sequential thin layer chromatography RESULTS: Of the 219 patients analysed, 131 were confirmed to be suffering from MPS. Quantitation of urinary GAGs alone would have missed 60 low GAG excreting MPS patients and misdiagnosed 26 high GAG excreting nonMPS as MPS patients. Further qualitative analysis and enzyme estimation were needed to identify these 60 low GAG excreting MPS patients and 26 high GAG excreting non MPS patients. CONCLUSION: These results emphasize that quantitation of urinary GAGs alone cannot diagnose MPS patients, it should be coupled with qualitative analysis and enzyme estimations for differential/definitive diagnosis.

Clinical and laboratorial study of 19 cases of mucopolysaccharidoses

The mucopolysaccharidoses (MPS) are a heterogeneous group of inborn errors of lysosomal glycosaminoglycan (GAG) metabolism. The importance of this group of disorders among the inborn errors of metabolism led us to report 19 cases. METHOD: We performed clinical, radiological, and biochemical evaluations of the suspected patients, which allowed us to establish a definite diagnosis in 19 cases. RESULTS: Not all patients showed increased GAG levels in urine; enzyme assays should be performed in all cases with strong clinical suspicion. The diagnosis was made on average at the age of 48 months, and the 19 MPS cases, after a full clinical, radiological, and biochemical study, were classified as follows: Hurler -- MPS I (1 case); Hunter -- MPS II (2 cases); Sanfilippo -- MPS III (2 cases); Morquio -- MPS IV (4 cases); Maroteaux-Lamy -- MPS VI (9 cases); and Sly -- MPS VII (1 case). DISCUSSION: The high relative frequency of Maroteaux-Lamy disease contrasts with most reports in the literature and could express a population variability

Discontinuous electrophoresis of glycosaminoglycans: a screening method for mucopolysaccharidoses.

A modified discontinuous electrophoretic method for the separation of standard and urinary glycosaminoglycans has been reported. The merits of the method are the simple and easy to handle apparatus, non-requirement of elaborate cooling system, sensitivity and high reproducibility of the results and applicability of the method for the preliminary grouping of the MPS patients to reduce the number of enzyme assays to be done.

A useful routine for biochemical detection and diagnosis of mucopolysaccharidoses

As mucopolissacaridoses (MPS) constituem, devido às suas características bioquímicas, genéticas e clínicas, um grupo grande e heterogêneo dentro das doenças lisôssomicas de depósito (LSD), e säo causadas pela deficiência de enzimas específicas que säo responsáveis pela quebra de gicosaminoglicanos (GAGs) em passos diferentes da sua rota de degradaçäo. Sendo as MPS responsáveis por aproximadamente 32 por cento dos erros inatos do metabolismo (EIM) e 54 por cento das LSD identificadas em nosso laboratório (Laboratório Regional dos Erros Inatos do Metabolismo (RLIEM), Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre), que é um centro de referência para o diagnóstico de LSD no Brasil, nós decidimos implantar uma rotina para detecçäo e o diagnóstico diferencial de MPS em pacientes com características clínicas sugestivas deste grupo de doenças.

Storage disorders presenting like mucopolysaccharidosis.

The term dysostosis multiplex is specifically applied to the group of radiological features collectively found in a number of specific metabolic disorders including the mucopolysaccharidoses, mucolipidosis, mannosidosis, fucosidosis and several other rarer conditions. We report eight cases of mannosidosis, fucosidosis and mucolipidosis with special emphasis on the differentiation from the more common mucopolysaccharidoses.

Estudio bioquímico de un paciente con enfermedad lisosomal heredometabólica / Biochemical study of a patient with lysosomal inherited metabolic disease

Se reporta el caso de una niña de 18 meses de edad que presenta características fenotípicas de tipo "hurleroide, a la cual se le realizó la determinación de las enzimas relacionadas con el metabolismo de los mucopolisacáridos (MPS), así como la caracterización cinética de la enzima denominada alfa-L-iduronidasa, cuya deficiencia condujo al diagnóstico de dicha enfermedad

As mucopolissacaridoses / The mucopolysaccharidoses

Neste artigo, as mucopolissacaridoses säo revisadas de forma sucinta e ilustradas com relatos de casos típicos

Estudo ultrastrutural de biópsias de conjuntiva em doenças metabólicas do sistema nervoso / Ultraestructural study of conjunctival biopsies in metabolic diseases of the nervous system

Quarenta biópsias de conjuntivas obtidas de um número igual de crianças portadoras de doenças metabólicas do SNC, ou supostas de tal acometimento, foram analisadas do ponto de vista ultrastrutural. Em 20 casos foram observadas alteraçöes ultrastruturais que possibilitam firmar o diagnóstico de mucopolissacaridose em 8, gangliosidose GM1 em 6, distrofia neuro-axonal infantil em 4, gangliosidose GM1 em um e forma infantil tardia de lipofuscinose ceróide em um. Nos 20 casos em que o exame revelou-se negativo, este era esperado em dois (doença de Leigh e de Hallervorden-Spatz); em dois, o resultado revelou-se falso negativo (leucodistrofia metacromática e adrenoleucodistrofia); em 12 casos sua negatividade permitiu afastar doença de acúmulo; em 4 casos suspeitos de lipofuscinose ceróide seu resultado foi inconclusivo. O estudo ultrastrutural de biópsias de conjuntiva é um instrumento importante para o diagnóstico de doenças metabólicas do SNC