Mucopolisacaridosis III. Revisión bibliográfica / Mucopolysaccharidosis III. Bibliographic review

Mucopolisacaridosis de tipo III es una enfermedad rara, con una incidencia de 1 en 70 000 nacidos vivos, es la más frecuente dentro del grupo de Mucopolisacaridosis y se produce por un defecto en la vía del metabolismo del heparan sulfato. Se caracteriza por afectar a mayor profundidad el sistema nervioso central, el paciente tiene un desarrollo normal hasta aproximadamente los 1 a 3 años de edad y posteriormente empieza con deterioro progresivo, cursa con retraso del desarrollo, alteración del comportamiento y trastorno del sueño agregándose déficit motor y cuadros infecciosos, culminando en un estado de postración. La esperanza de vida oscila entre los 20 a 30 años, aunque depende del fenotipo y la principal causa de muerte fue la neumonía. El diagnóstico definitivo se consigue mediante pruebas genómicas y ensayo enzimático. No cuenta con tratamiento curativo, únicamente con paliación y soporte ante las complicaciones que va desarrollando

Mucopolysaccharidosis III is a rare disease, with an incidence of 1 in 70 000 live births, it is the most frequent within the group of Mucopolysaccharidosis and is caused by a defect in the heparan sulfate metabolism pathway. It is characterized by affecting the central nervous system in greater depth, the patient has a normal development until approximately 1 to 3 years of age and later begins with progressive deterioration, courses with developmental delay, behavioral alteration and sleep disorder, adding motor deficits and infectious pictures, culminating in a state of prostration. Life expectancy ranges from 20 to 30 years, although it depends on the phenotype, and the main cause of death is pneumonia. Definitive diagnosis is achieved by genomic tests and enzymatic assay. It does not have curative treatment, only palliation and support in the face of the complications that it develops.

Mucopolysacaridosis type iiib misdiagnosed as an autistic spectrum disorder: a case report and literature review / Mucopolissacaridose tipo iii b mal diagnosticada como transtorno de espectro autista: relato de caso e revisão de literatura

ABSTRACT Objective: To report a rare case of mucopolysaccharidosis IIIB in a pediatric patient, with emphasis on the description of the clinical manifestations and the early diagnosis. Case description: A 14-year-old male patient, who presented regression of neuropsychomotor development since his three years and six months old, with speech loss and frequent falls, evolving with behavioral changes, with agitation and aggressiveness. Although being diagnosed with autism, there was no response to the established treatment; he was subsequently submitted to metabolic investigation, which lead to the diagnosis of Mucopolysaccharidosis IIIB. Comments: Identifying a metabolic disorder requires connecting multiple signs and symptoms, as well as eliminating other apparent causes. MPS IIIB is a diagnostic challenge, particularly in the early stages and in the absence of a family history of the disease.

RESUMO Objetivo: Relatar o caso raro de um paciente pediátrico com mucopolissacaridose III B, com ênfase na descrição de manifestações clínicas. Descrição do caso: Paciente masculino de 14 anos que, a partir dos 3 anos e 6 meses de idade, apresentou regressão do desenvolvimento neuropsicomotor, com perda da fala e quedas frequentes, evoluindo com alterações comportamentais, agitação e agressividade. Diagnosticado como autista, não obteve resposta ao tratamento estabelecido, sendo posteriormente submetido à investigação metabólica, que evidenciou o diagnóstico de mucopolissacaridose III B. Comentários: A identificação de um distúrbio metabólico exige conectar vários sinais e sintomas, além de eliminar outras causas aparentes. A mucopolissacaridose III B é um desafio diagnóstico, particularmente nos estágios iniciais e na ausência de história familiar da doença.

Determination of Reference Values for Alpha-N-Acetylglucosaminidase Activities in Patients with Sanfilippo Type B Disease and Control Population in Colombia

Abstract Sanfilippo B is a lysosomal disorder characterized by the pathological accumulation of heparan sulfate. It is caused by mutations in the NAGLU gene that codes for the alpha-N-acetylglucosaminidase enzyme. The objective of this study was to determine the reference values and frequency of Sanfilippo B in Colombia through an enzyme analysis of leukocytes extracts. We aim to inform the community and the health system so that they can work in a preventive way, providing an early diagnosis of patients and thus providing an appropriate management of the symptoms. We carried out an endpoint assay that indirectly quantifies NAGLU activity through the cleavage of 4-methylumbelliferone from the 4-methylumbelliferyl-2-acetamido-2-deoxy-α-D-glucopyranoside substrate. The activity of 463 healthy volunteers (Range: 0.6 - 4 nmol/mg/h, Median: 1.69 +/- 0.73) as well as 462 patients referred for clinical suspicion, was calculated. From the last group, 7 cases turned out to be positive (Range: 0 - 0.24 nmol/mg/h, Median: 0.13 +/- 0.09). The cut-off point according to ROC analysis between affected patients and controls was 0.42 nmol/mg/h. To our knowledge, this study is the first in Colombia where an estimated frequency of Sanfilippo type B is calculated by providing enzyme activity ranges and a cut-off point.

Development of a Clinical Algorithm for the Early Diagnosis of Mucopolysaccharidosis III

Abstract Mucopolysaccharidosis III (MPS III) is a rare inherited metabolic disease primarily affecting the central nervous system, leading to developmental and/or speech regression. Early diagnosis of the disease is important to introduce appropriate management measures and to optimize therapeutic outcomes. The diagnosis of MPS III is often significantly delayed due to the rarity of the disease, the more attenuated somatic presentation compared to other MPS types, and the symptom overlap with other developmental disorders. To shorten the time to diagnosis, a list of eight early signs and symptoms was identified through an expert system approach by a global, multidisciplinary working group of 13 specialists with expertise in various aspects of MPS and developmental disorders and three parents of MPS III patients. Coarse facial features and persistent hirsutism or prominent, thick eyebrows were identified as the most important MPS III early signs. The list of eight early MPS III signs and symptoms is the first step towards the development of a clinical algorithm aiming to identify neonates and infants with MPS III before the onset of neurocognitive damage, ultimately shortening the diagnostic journey of MPS III patients.

Determinación de endogamia mediante método de isonimia en la población de Runta, Boyacá, Colombia / Determination of inbreeding by isonymy in the population of Runta, Boyacá, Colombia

Resumen Introducción. Dado el hallazgo de enfermedades raras de herencia recesiva en un número mayor de pacientes al esperado, estudios recientes han sugerido la ]presencia de un aislado poblacional en la vereda de Runta, en el departamento de Boyacá, Colombia. Esto indica la probabilidad de una tasa de consanguinidad aumentada en dicha población. Objetivos. Determinar los parámetros de endogamia mediante isonimia para analizar la estructura poblacional de la vereda Runta y ayudar a elucidar las causas de la aparición de estas enfermedades. Materiales y métodos. Se establecieron seis parámetros indicativos de estructura poblacional basados en los apellidos registrados en la base de datos del Sistema de Identificación y Selección de Potenciales Beneficiarios de Programas Sociales de los habitantes de Runta. Resultados. Se obtuvo coeficiente de endogamia (θii) de 0.0083, alfa de Fisher (α) de 30.0447 y estimativos A, B y C de 0.0379, 0.3413 y 0.4669, respectivamente. La mayoría de los individuos se encontraron agrupados en los apellidos más frecuentes de la población. Los parámetros de isonimia en Runta son similares a los de comunidades aisladas descritas en la literatura. Conclusión. Los resultados soportan la hipótesis previa de que se está ante un aislado genético en una población muy cercana a la capital del departamento de Boyacá.

Abstract Introduction: Recent studies have suggested the presence of a genetic isolate in the village of Runta, located in the department of Boyacá, Colombia, given the finding of a larger number of patients with rare diseases than expected for this population. This finding indicates the probability of an increased rate of inbreeding in this community. Objectives: To determine inbreeding parameters using isonymy to analyze the population structure of this village and to help elucidate the causes of these diseases. Materials and methods: Six parameters indicative of population structure were established based on the surnames registered in the database of the Potential Beneficiaries of Social Programs Identification and Selection System of the inhabitants of Runta. Results: Results showed an inbreeding coefficient (θii) of 0.0083, Fisher's alpha (α) of 30.0447 and A, B and C estimates of 0.0379, 0.3413 and 0.4669, respectively. Most individuals had the most popular surnames of the village, while isonymy parameters in Runta were found to be similar to those of isolated communities previously described in the literature. Conclusion: These results support the hypothesis that there is indeed a genetic isolate located near the capital of the department of Boyacá.

Genética clínica comunitaria: exploración de patología genética en Boyacá, Colombia / Clinical community genetics: exploring genetic disorders in Boyacá, Colombia

RESUMEN Objetivo Explorar la presencia de patología genética sindrómica en el Departamento de Boyacá, mediante un acercamiento de medicina genética comunitaria. Materiales y Métodos Un grupo conformado por genetistas, neurólogo pediátrico y genetista bioquímico, llevó a cabo jornadas clínicas en las cuales se evaluaron pacientes con sospecha de enfermedad genética. Se obtuvieron datos demográficos, epidemiológicos y clínicos y se realizó el cálculo de frecuencias de los mismos. En los centros de referencia visitados se realizaron actividades de capacitación al personal médico. Resultados Se encontraron dos agrupamientos genéticos: MPSIII y Síndrome de Ellis Van Creveld, con incidencias mayores a lo reportado en la literatura, además una alta frecuencia de patologías de herencia autosómica recesiva, así como sospecha de síndromes de microdeleción-microduplicación. Conclusiones Se deben establecer mecanismos no convencionales de atención médica para facilitar el acceso a las comunidades a un diagnóstico y tratamiento adecuados en genética. Se espera que el apoyo brindado a los pacientes, familias y personal asistencial de los hospitales a través de las jornadas clínicas y la capacitación, permitan alcanzar este objetivo y a la vez sea un punto de inicio de procesos de prevención primaria y secundaria.(AU)

ABSTRACT Objectives To explore the incidence of syndromic genetic pathologies in Boyacá, Colombia, through a community genetics approach. Materials and Methods A group made up by different medical specialists (geneticists, a pediatric neurologist, and a biochemical geneticist) developed clinical campaigns, in which patients with clinical suspicion of genetic diseases were involved. Demographic, epidemiological and clinical data were collected, and frequency calculations were made based on the collected data. Several training workshops for health personnel were done in each center visited. Results Two genetic clusters were found: mucopolysaccharidosis type III, and Ellis-Van Creveld Syndrome, both of them with higher incidences than those found in the literature. Also, a high frequency of autosomal recessive diseases was found, as well as microdeletion/microduplication syndromes. Conclusions Conventional mechanisms of medical attention must be established, in order to facilitate the access to an appropriate diagnosis and treatment. This work intended to provide support to patients, families and health care services personnel through the workshops and clinical campaigns, and to become a starting point to develop primary and secondary prevention processes.(AU)

Long-term clinical course of a patient with mucopolysaccharidosis type IIIB / 소아과

Mucopolysaccharidosis type III (MPS III) is a rare genetic disorder caused by lysosomal storage of heparan sulfate. MPS IIIB results from a deficiency in the enzyme alpha-N-acetyl-D-glucosaminidase (NAGLU). Affected patients begin showing behavioral changes, progressive profound mental retardation, and severe disability from the age of 2 to 6 years. We report a patient with MPS IIIB with a long-term follow-up duration. He showed normal development until 3 years. Subsequently, he presented behavioral changes, sleep disturbance, and progressive motor dysfunction. He had been hospitalized owing to recurrent pneumonia and epilepsy with severe cognitive dysfunction. The patient had compound heterozygous c.1444C>T (p.R482W) and c.1675G>T (p.D559Y) variants of NAGLU. Considering that individuals with MPS IIIB have less prominent facial features and skeletal changes, evaluation of long-term clinical course is important for diagnosis. Although no effective therapies for MPS IIIB have been developed yet, early and accurate diagnosis can provide important information for family planning in families at risk of the disorder.

Mucopolissacaridose III B: revisão dos aspectos clínicos com ênfase no diagnóstico precoce

Objetivo: Realizar uma revisão da literatura sobre mucopolissacaridose tipo III, enfatizando as manifestações clínicas e o diagnóstico precoce. Fontes de dados: Bases de dados MEDLINE e artigos selecionados pertinentes ao assunto, publicados até o momento, buscados de acordo com os seguintes termos: ?mucopolissacaridose?, ?Sanfilippo?, ?licosaminoglicanos?. Síntese dos dados: As mucopolissacaridoses (MPS) III (síndrome de Sanfilippo) são doenças genéticas, causadas por deficiências enzimáticas, com consequente acúmulo lisossomal de mucopolissacarideos nos tecidos, resultando em sinais e sintomas permanentes e progressivos. São subdivididas em quatro subtipos: III-A, III-B, III-C e III-D, de acordo com a deficiência enzimática específica. São caracterizadas por fenótipo clínico característico, combinado com doença neurodegenerativa precoce e grave, com proeminentes distúrbios de comportamento e convulsões. O diagnóstico oportuno e precoce é fundamental para não só melhorar o tratamento de suporte do paciente, como também para oferecer à família aconselhamento genético. Conclusões: Enfatizamos a necessidade de reconhecimento, pelo pediatra, do fenótipo MPS III típico.

Estudio de las enzimas lisosomales N-acetil-a-D-glucosaminidasa y arilsulfatasa A en adultos cubanos / Assay of lysosomal N-acetyl-a-D-glucosaminidase and arylsulfatase A activities in Cuban adults

El objetivo de este estudio fue determinar, en una muestra de individuos cubanos, un rango preliminar de valores normales de actividad específica de N-acetil- a-D-glucosaminidasa y arilsulfatasa A, enzimas deficientes en la mucopolisacaridosis tipo III B y la leucodistrofia metacromática, respectivamente. Se realizó una investigación de corte transversal, en muestras de sangre de 38 individuos adultos. Se realizó la extracción de los leucocitos y se determinó la actividad específica de las enzimas por métodos espectrofotométricos. Todos los participantes fueron caracterizados desde el punto de vista clínico como sanos para ambas enfermedades. Se obtuvieron valores medios de actividad específica de N-acetil-a-D-glucosaminidasa y arilsulfatasa A de 1,52±0,30 y 121,37±20,14 nmol/mg/h, respectivamente. No se encontraron diferencias significativas en relación a las características étnicas para ninguna de las dos enzimas (p<0,05). Este constituye el primer estudio cubano en el cual se publican rangos de actividad específica para estas enzimas en individuos cuya condición de sanos y no relacionados familiarmente con la enfermedad ha sido clínicamente demostrada. El análisis de un mayor número de muestras permitirá establecer los puntos de corte que dotarán al diagnóstico bioquímico de estas enfermedades de una mayor confiabilidad.

The aim of this study was to determine, in a sample of Cuban individuals, a preliminary range of normal values of N-acetyl-a-D-glucosaminidase and arylsulfatase A activity, enzymes that are deficient in mucopolysaccharidosis type III B and metachromatic leukodystrophy, respectively. A cross-sectional research was conducted. Blood samples were obtained out of 38 adult individuals. The leucocytes were extracted and the specific enzymatic activity was assayed by spectrophotometric methods. All participants were characterized from the clinical point of view as healthy for both diseases. Average values of N-acetyl-a-D-glucosaminidase and arylsulfatase A specific activities of 1.52 ± 0.30 and 121.37 ± 20.14 nmol/mg/h, respectively were obtained. There were no significant differences related to ethnicity for any of the two enzymes (p <0.05). This is the first Cuban study in which ranges of activity for these enzymes have been reported in healthy individuals whose healthy and non-familiarly related with the disease status have been clinically demonstrated. The analysis of more samples will establish the cutoff points that will increase the reliability of the biochemical diagnosis of these diseases.