Aspectos neurobiológicos del Síndrome de Rett

El Síndrome de Rett es un trastorno monogénico ligado al cromosoma X, de carácter progresivo que afecta el neurodesarrollo principalmente de niñas durante las primeras etapas del ciclo vital. Su etiología se debe principalmente a las mutaciones de cambio de nucleótido único con pérdida de función del gen MECP2. Este gen codifica para la proteína del mismo nombre cuya principal función es actuar como un represor global de la transcripción mediante el reconocimiento de zonas metiladas de islas CpG y el reclutamiento de factores correpresores que modulan la expresión génica desacetilando histonas. Dentro de las principales alteraciones estructurales asociadas al síndrome se encuentran una morfología neuronal atípica con tamaño del soma neuronal y número de espinas dendríticas reducido, además de alteraciones neuroquímicas sobre todo en la señalización GABAérgica llevando a una desregulación entre señales excitatorias e inhibitorias, causando epilepsia. También se han descrito una serie de alteraciones metabólicas, oxidativas e inflamatorias. El tratamiento hasta ahora se ha enfocado más en buscar un alivio sintomático para las manifestaciones del síndrome pero se ha desarrollado recientemente terapia génica con el objetivo de tratar desde sus bases neurogenéticas la patología y evitar así el desarrollo alterado durante la niñez.

Rett Syndrome is a monogenic disorder linked to the X chromosome, of a progressive nature that affects neurodevelopment mainly in girls during the first stages of the life cycle. Its etiology is mainly due to loss-of-function single nucleotide change mutations of the MECP2 gene. This gene codes for the protein of the same name whose main function is to act as a global repressor of transcription through the recognition of methylated areas of CpG islands and the recruitment of corepressor factors that modulate gene expression by deacetylating histones. Among the main structural alterations associated with the syndrome are an atypical neuronal morphology with a size of the neuronal soma and a reduced number of dendritic spines, in addition to neurochemical alterations, especially in the GABAergic signal, leading to dysregulation between excitatory and inhibitory signals, causing epilepsy. A series of metabolic, oxidative, and inflammatory disorders have also been described. Until now, treatment has focused more on seeking symptomatic relief for the manifestations of the syndrome, but gene therapy has recently been developed with the aim of treating the pathology from its neurogenetic bases and thus avoiding altered development during childhood.

Enseñanza de funciones comunicativas orientadas a la interacción social en un caso de síndrome de Rett / Teaching of social interaction-oriented communication functions in a case of Rett syndrome

Antecedentes y objetivo: La elección y las peticiones han sido tradicionalmente los objetivos de la intervención de la comunicación aumentativa y alternativa (CAA) en el síndrome de Rett (SR). Sin embargo, hay escasos antecedentes sobre la enseñanza de otras funciones de la comunicación. El objetivo de este estudio es la enseñanza de funciones comunicativas orientadas a la interacción social usando símbolos de CAA. Materiales y métodos: Mediante un diseño de caso único de línea base entre conductas se investigó hasta qué punto una niña con SR de 11 años podría aprender funciones comunicativas orientadas a la interacción social, específicamente, a realizar cumplidos, protestar de forma asertiva y pedir favores seleccionando símbolos de CAA en un tablero de comunicación por medio de la mirada. La intervención consistió en la creación de oportunidades para el aprendizaje de estas funciones y la aplicación de incitaciones. La línea base, la intervención y el mantenimiento se implementaron en un aula de un colegio de educación especial, con diferentes personas y materiales para promover la generalización. Resultados: Después de la intervención la participante mostró su capacidad de realizar cumplidos («¡Qué guapa eres», «Eres buena» y «Me gusta tu adorno»), de pedir favores («Me dejas ver Dora la exploradora», «¿Me prestas tu juguete?» y «Me gustaría descansar») y de protestar asertivamente («No me apetece», «Mejor más tarde» y «Prefiero hacerlo luego») sin incitaciones; además fue capaz de realizar comentarios espontáneos y demostró aprendizaje sostenido en el tiempo. Conclusiones: Se concluye que esta intervención comunicativa ha tenido el potencial de mejorar la comunicación social y ayudar al desarrollo de relaciones sociales entre la participante y sus compañera/os, maestras y terapeutas.(AU)

Background and aims: Choice making and requesting have traditionally been the focus of Augmentative and Alternative Communication (AAC) intervention in Rett syndrome (RS). However, scant literature exists about some other communication functions teaching. The aim of this study is to teach the social interaction function of communication using AAC symbols. Materials and methods: A multiple baseline study was carried out to investigate to what extent a girl with Rett syndrome aged 11 would learn to communicate for social interaction making compliments, asking for favours, and protesting assertively selecting AAC symbols using an eye-gaze system. The intervention consisted of the creation of opportunities for learning these communication functions and the application of prompts. Baseline, intervention, and maintenance were all implemented within a special education classroom in a public school, with different people and different materials, from the very onset, to promote generalization. Results: After intervention, the participant displayed the ability to make compliments («How pretty you are!»; «How nice you are!» and «I like your costume jewellery!»), to ask for favours («Let me see Dora the explorer»; «May I borrow your toy?»; «I would like to rest»), and to protest assertively («I don’t fancy it»; «Later the better» and «I’d rather do it later») without any prompting, learning generalization outside the learning contexts and sustained learning over time. Conclusions: It is concluded that this communication intervention had the potential to improve social communication and assist in the development of social relationships between the participant and her peers, teachers, and therapists.(AU)

Mecanismos epigenéticos involucrados en la génesis del autismo / Epigenetic mechanisms involved in the genesis of autism

Resumen El autismo es un trastorno del neurodesarrollo de base neurobiológica, caracterizado por alteración en la interacción social y la comunicación, intereses restringidos y conductas estereotipadas. Se relaciona con trastornos en la sinaptogénesis y a multiples etiologías. La identificación de factores epigenéticos implicados en la génesis del autismo permiten una mejor comprensión de los mecanismos moleculares invo lucrados. Nuestro objetivo fue analizar los mecanismos epigenéticos relacionados al desarrollo del autismo, puntualizando entidades específicas y sus mecanismos fisiopatológicos. Analizamos de qué manera se rela cionan los trastornos en la metilación del ADN, la modificación de las histonas, la remodelación cromosómica y la regulación mediada por el ARN no codificantes con diversos síndromes genéticos como el frágil X, Rett, Mecp2patías, Phelam McDermid, tóxicos prenatales como el alcohol, ácido valproico, cannabis y ambientales cómo el estrés materno, todos ellos asociados a una mayor prevalencia de autismo. En conclusión, el recono cimiento de estos mecanismos abre nuevas posibilidades para la prevención, y probablemente en un futuro, en las entidades genéticas, permitirá el desarrollo de tratamientos específicos con modificaciones a la medida de cada entidad.

Abstract Autism is a neurobiological developmental disorder characterized by poor social interaction and communication, narrow interests, and stereotyped behaviors. It has been associated with disorders of synaptogenesis and multiple etiologies. The iden tification of the epigenetic factors involved in the genesis of autism allows a better understanding of the molecular mechanisms involved. Our objective was to analyze the epigenetic mechanisms related to the development of autism, specifying specific entities and their pathophysiological mechanisms. We analyze how DNA methylation disorders, histone modification, remodeling and chromosomal regulation mediated by non-coding RNA are related to various genetic syndromes such as fragile X, Rett, Pathias Mecp2, Phelam McDermid, prenatal toxins such as alcohol, valproic. acid, cannabis, and environmental toxins such as maternal stress, all associated with a higher prevalence of autism. In conclusion: the recognition of these mechanisms opens up new possibilities for preven tion and it is likely that, in genetic entities, it will allow the development of specific treatments with modifications tailored to each entity.

[Rett syndrome: report of a new pathogenic variant and review of the literature regarding two clinical cases.] / Síndrome de Rett: reporte de una nueva variante patogénica y revisión de la literatura a propósito de dos casos clínicos.

INTRODUCCIÓN: El síndrome de Rett es un trastorno del neurodesarrollo con una frecuencia estimada de 1/10,000 recién nacidos vivos, el cual se presenta con un modelo de herencia ligado al cromosoma X. Las variantes patogénicas en el gen MECP2, el cual codifica para una proteína que participa en el desarrollo y la diferenciación del sistema nervioso central, causan este síndrome. El objetivo de este trabajo fue describir dos casos de síndrome de Rett, uno de ellos con una nueva variante del gen MECP2. CASOS CLÍNICOS: El primer caso se trata de una paciente de 5 años con microcefalia y regresión del neurodesarrollo desde los 3 años. Clínicamente se diagnosticó de síndrome de Rett en estadio III. Se realizó la secuenciación del gen MECP2 y se identificó una variante probablemente patogénica en estado heterocigoto, c.606delC (p.Thr203Argfs*7), que no ha sido reportada previamente. El segundo caso es una paciente de 17 años, referida por discapacidad intelectual grave, que se encontró clínicamente en estadio IV. Se realizó la secuenciación de MECP2 y se identificó una variante patogénica [c.880C>T(p.Arg294*)] ya descrita previamente. CONCLUSIONES: El diagnóstico clínico de síndrome de Rett se llevó a cabo con criterios establecidos. La confirmación diagnóstica fue mediante la secuenciación de MECP2. Para el correcto abordaje de los trastornos del neurodesarrollo es primordial conocer el fenotipo de síndrome de Rett, así como optar por el análisis molecular para la confirmación del diagnóstico. Los pacientes con síndrome de Rett requieren un seguimiento interdisciplinario para disminuir el impacto de las complicaciones. BACKGROUND: Rett syndrome is an X-linked neurodevelopmental disorder with an estimated frequency of 1/10,000 live births caused by hetereozygous pathogenic variants in the MECP2 gene, whose protein participates in the development and differentiation of the central nervous system. This study aimed to describe two cases with Rett syndrome diagnosis, one of them with a new variant of the MECP2 gene. CASE REPORTS: We first describe the case of a 5-year-old female with microcephaly and neurodevelopmental regression starting at 3 years old, clinically corresponding to stage III Rett syndrome. Sequencing of the MECP2 gene identified a heterozygous likely pathogenic variant [c.606delC (p.Thr203Argfs*7)] not reported previously. The second case is a 17-year-old female, referred due to severe intellectual disability, clinically found on stage IV. MECP2 sequencing was performed identifying a pathogenic variant previously described [c.880C> T (p.Arg294 *)]. CONCLUSIONS: Rett syndrome clinical diagnosis was carried out based on established criteria. MECP2 sequencing confirmed the diagnosis. For neurodevelopmental disorders approach, it is essential to know the phenotype of Rett syndrome and select the molecular tool for the diagnosis. Patients with Rett syndrome require interdisciplinary follow-up for reducing the impact of complications.

Síndrome de Rett: reporte de una nueva variante patogénica y revisión de la literatura a propósito de dos casos clínicos / Rett syndrome: report of a new pathogenic variant and review of the literature regarding two clinical cases

Resumen Introducción: El síndrome de Rett es un trastorno del neurodesarrollo con una frecuencia estimada de 1/10,000 recién nacidos vivos, el cual se presenta con un modelo de herencia ligado al cromosoma X. Las variantes patogénicas en el gen MECP2, el cual codifica para una proteína que participa en el desarrollo y la diferenciación del sistema nervioso central, causan este síndrome. El objetivo de este trabajo fue describir dos casos de síndrome de Rett, uno de ellos con una nueva variante del gen MECP2. Casos clínicos: El primer caso se trata de una paciente de 5 años con microcefalia y regresión del neurodesarrollo desde los 3 años. Clínicamente se diagnosticó de síndrome de Rett en estadio III. Se realizó la secuenciación del gen MECP2 y se identificó una variante probablemente patogénica en estado heterocigoto, c.606delC (p.Thr203Argfs*7), que no ha sido reportada previamente. El segundo caso es una paciente de 17 años, referida por discapacidad intelectual grave, que se encontró clínicamente en estadio IV. Se realizó la secuenciación de MECP2 y se identificó una variante patogénica [c.880C>T(p.Arg294*)] ya descrita previamente. Conclusiones: El diagnóstico clínico de síndrome de Rett se llevó a cabo con criterios establecidos. La confirmación diagnóstica fue mediante la secuenciación de MECP2. Para el correcto abordaje de los trastornos del neurodesarrollo es primordial conocer el fenotipo de síndrome de Rett, así como optar por el análisis molecular para la confirmación del diagnóstico. Los pacientes con síndrome de Rett requieren un seguimiento interdisciplinario para disminuir el impacto de las complicaciones.

Abstract Background: Rett syndrome is an X-linked neurodevelopmental disorder with an estimated frequency of 1/10,000 live births caused by hetereozygous pathogenic variants in the MECP2 gene, whose protein participates in the development and differentiation of the central nervous system. This study aimed to describe two cases with Rett syndrome diagnosis, one of them with a new variant of the MECP2 gene. Case reports: We first describe the case of a 5-year-old female with microcephaly and neurodevelopmental regression starting at 3 years old, clinically corresponding to stage III Rett syndrome. Sequencing of the MECP2 gene identified a heterozygous likely pathogenic variant [c.606delC (p.Thr203Argfs*7)] not reported previously. The second case is a 17-year-old female, referred due to severe intellectual disability, clinically found on stage IV. MECP2 sequencing was performed identifying a pathogenic variant previously described [c.880C> T (p.Arg294 *)]. Conclusions: Rett syndrome clinical diagnosis was carried out based on established criteria. MECP2 sequencing confirmed the diagnosis. For neurodevelopmental disorders approach, it is essential to know the phenotype of Rett syndrome and select the molecular tool for the diagnosis. Patients with Rett syndrome require interdisciplinary follow-up for reducing the impact of complications.

Factores de riesgo perinatal asociados al trastorno del espectro autista y al síndrome de Rett / Perinatal risk factors associated with autistic spectrum disorder and the Rett syndrome

Resumen El propósito de este proyecto fue identificar los factores de riesgo perinatal asociados al trastorno del espectro autista (TEA) y al síndrome de Rett y compararlos entre sí, estando enmarcado dentro de un estudio de tipo descriptivo. Para esta investigación se utilizó una unidad de análisis conformada por 421 historias clínicas, de las que 377 fueron de TEA y 44 de Rett, a las cuales se les aplicó un instrumento especializado en identificar factores de riesgo perinatales llamado Cuestionario Materno de Riesgo Perinatal (CMRP), con el que se encontró una gran prevalencia de niños nacidos por cesárea y que las ocupaciones de sus padres estaban relacionadas con los cuidados requeridos por el trastorno. Esta identificación de factores servirá para la toma de precauciones a nivel clínico médico y a nivel de prevención de los riesgos asociados al trastorno del espectro autista y el síndrome de Rett.

Abstract The purpose of this project was to identify the perinatal risk factors associated with Autism Spectrum Disorder (ASD) and Rett Syndrome and compare them to each other, being framed within a descriptive study; For this research, an analysis unit consisting of 421 medical records was used, of which 377 were from ASD and 44 from Rett, to which a specialized instrument was applied to identify perinatal risk factors called the Maternal Perinatal Risk Questionnaire (MPRQ ), which found a high prevalence of children born by caesarean section and that their parents' occupations were related to the care required by the disorder. This identification of factors will serve to take precautions at the medical clinical level and at the level of prevention of the risks associated with Autism Spectrum Disorder and Rett Syndrome.

Rett syndrome: the Brazilian contribution to the gene discovery / Síndrome de Rett: a contribuição brasileira para a descoberta do gene

ABSTRACT A brief history of the syndrome discovered by Andreas Rett is reported in this paper. Although having been described in 1966, the syndrome was only recognized by the international community after a report by Hagberg et al. in 1983. Soon, its importance was evident as a relatively frequent cause of severe encephalopathy among girls. From the beginning it was difficult to explain the absence of male patients and the almost total predominance of sporadic cases (99%), with very few familial cases. For these reasons, it was particularly difficult to investigate this condition until 1997, when a particular Brazilian family greatly helped in the final discovery of the gene, and in the clarification of its genetic mechanism. Brief references are made to the importance of the MECP2 gene, 18 years later, as well as to its role in synaptogenesis and future prospects.

RESUMO Uma breve história de uma síndrome neurológica descoberta por Andreas Rett é relatada neste artigo. Embora tenha ocorrido em 1966, a síndrome só foi reconhecida pela comunidade internacional após um relato de Hagberget al, em 1983. Logo, sua importância ficou evidente como causa relativamente frequente de encefalopatia grave entre as crianças do sexo feminino. Desde o início, foi difícil explicar a ausência de envolvimento de pacientes do sexo masculino e a quase absoluta preponderância de casos esporádicos (99%), com muitos poucos casos familiares. Por essas razões, foi difícil investigar essa condição até 1997, quando uma família brasileira em particular ajudou muito na descoberta final do gene e no esclarecimento de seu mecanismo genético. São feitas referências sucintas à importância do gene MECP2, dezoito anos depois, bem como ao seu papel na sinaptogênese e nas perspectivas futuras.

Diagnóstico de Rett. Presentación de un caso / Diagnosis of Rett. Presentation of a case

El síndrome de Rett es un trastorno neurológico que afecta casi únicamente a las niñas y mujeres, cuya incidencia en la población general es de un caso por cada 10 000 mujeres, su diagnóstico se basa en la observación y evaluación clínica(AU)

Síndrome de Rett: Análisis molecular del gen MECP2 en pacientes chilenas / Rett syndrome: MECP2 gene molecular analysis in Chilean patients

INTRODUCCIÓN: El síndrome de Rett (RTT) es un trastorno neurológico progresivo caracterizado por producir una regresión del desarrollo psicomotor en niñas previamente sanas. La mayoría de los casos son causados por variantes patogénicas en el gen MECP2, que codifica para la proteína methyl CpG- binding protein 2. OBJETIVO: Describir la frecuencia y el tipo de variantes patogénicas en MECP2 en mujeres chilenas con diagnóstico clínico de RTT. PACIENTES Y MÉTODO: Se invitó a participar en este estudio a mujeres chilenas con sospecha clínica de RTT. Se reunió información clínica mediante un cuestionario. Se analizaron variantes patogénicas en MECP2 mediante el método de secuenciación de Sanger y se utilizó Multiple Ligation-dependant Probe Amplification (MLPA) para la detección de duplicaciones y deleciones. RESULTADO: El estudio incluyó 14 pacientes con sospecha de RTT, de las cuales 8 (57%) pacientes tuvieron variantes patogénicas. Las restantes permanecen sin diagnóstico molecular. CONCLUSIÓN: Variantes patogénicas en MECP2 están presentes en pacientes chilenas con RTT. Es probable que haya otros genes o diagnósticos involucrados en las pacientes sin hallazgos en MECP2. A partir de este trabajo, el diagnóstico molecular está disponible en Chile.

INTRODUCTION: Rett syndrome (RTT) is a progressive neurological disorder characterized by regres sion of psychomotor development in previously healthy girls. Most cases are due to pathogenic va riants in the MECP2 gene which encodes for the methyl CpG-binding protein 2. OBJECTIVE: To des cribe the frequency and type of pathogenic variants in the MECP2 gene in Chilean female patients with clinical diagnosis of RTT. PATIENTS AND METHOD: Chilean women with clinical suspicion of RTT were invited to participate in the study. Clinical data were collected through a questionnaire. MECP2 pathogenic variants were analyzed by Sanger sequencing method and Multiplex Ligation-dependent Probe Amplification (MLPA) was used to detect duplications or deletions. RESULTS: The study in cluded 14 patients with suspected RTT, of which eight (57%) patients had pathogenic variants. The other patients remain without molecular diagnosis. CONCLUSIONS: Pathogenic variants in MECP2 are present in Chilean patients with RTT. It is likely that there are other genes or diagnoses involved in patients without MECP2 findings. As of this study, molecular diagnosis is available in Chile.

Diagnóstico de Rett. Presentación de un caso / Diagnosis of Rett. Presentation of a case

El síndrome de Rett es un trastorno neurológico que afecta casi únicamente a las niñas y mujeres, cuya incidencia en la población general es de un caso por cada 10 000 mujeres, su diagnóstico se basa en la observación y evaluación clínica(AU)

Transtornos autísticos e estratégias promotoras de cuidados: revisão integrativa / Trastornos autísticos y estratégias promotoras de cuidados: revisión integradora / Autistic disorders and care promotion strategies: integrative review

Objetivo analisar a produção científica brasileira recente sobre Transtornos do Espectro Autista, identificando as estratégias de cuidados investigadas. Método revisão integrativa de literatura na base de dados LILACS e na biblioteca virtual SciELO. Foram selecionados artigos publicados entre 2011 e 2017, utilizando os descritores Transtorno Autístico, Síndrome de Asperger e Síndrome de Rett. Resultados vinte e quatro artigos foram caracterizados e analisados descritivamente, com exposição dos seus níveis de evidência. Doze estudos (50%) representavam pesquisas descritivas, nível de evidência VI. Onze estudos (45,8%) equivaliam a delineamento não experimental, nível de evidência IV. A estratégia mais estudada foi de diagnóstico e avaliação para a prática clínica, com aplicação de instrumentos já validados, seguida de avaliação de resultados terapêuticos. Conclusão a produção científica brasileira atual sobre Transtorno do Espectro Autista mostrou-se direcionada para o enfoque diagnóstico nas áreas de fonoaudiologia e psicologia.

Objetivo analizar la producción científica brasileña reciente sobre Trastornos del Espectro Autista, identificando las estrategias de cuidados investigadas. Método revisión integradora de literatura en la base de datos LILACS y en la biblioteca virtual SciELO. Fueron seleccionados artículos publicados entre 2011 y 2017, utilizando los descriptores Trastorno Autístico, Síndrome de Asperger y Síndrome de Rett. Resultados veinte y cuatro artículos fueron caracterizados y analizados descriptivamente, con exposición de sus niveles de evidencia. Doce estudios (50%) representaban investigaciones descriptivas, nivel de evidencia VI. Once estudios (45,8%) correspondían a diseño no experimental, nivel de evidencia IV. La estrategia más estudiada fue de diagnóstico y evaluación para la práctica clínica, con aplicación de instrumentos ya validados, seguida de evaluación de resultados terapéuticos. Conclusión la producción científica brasileña actual sobre Trastorno del Espectro Autista se mostró orientada al enfoque diagnóstico en las áreas de fonoaudiología y psicología.

Objective to analyze the recent Brazilian scientific production about Autism Spectrum Disorders, identifying the investigated care strategies. Method integrative literature review in the database LILACS and in the virtual library SciELO. Articles published between 2011 and 2017 were selected, using the descriptors Autistic Disorder, Asperger Syndrome and Rett Syndrome. Results twenty four articles were characterized and analyzed descriptively, and their levels of evidence were presented. Twelve studies (50%) represented descriptive research, level of evidence VI. Eleven studies (45.8%) had non-experimental designs, level of evidence IV. The most studied strategy was the diagnosis and evaluation for clinical practice, by applying validated tools, followed by the assessment of therapeutic outcomes. Conclusion current Brazilian scientific production about Autism Spectrum Disorder was focused on diagnosis in speech therapy and psychology.

Síndrome de Rett: revisión de la literatura con primeros casos reportados en Colombia con caracterización clínica y molecular / Rett syndrome: review of the literature and first cases reported in Colombia with clinical characterization and molecular diagnosis

RESUMEN INTRODUCCIÓN: El síndrome de Rett es una condición neurológica severa y la segunda causa genética de retraso mental profundo en mujeres. Se genera por mutaciones en el gen MECP2 y es caracterizada por una pérdida de las ganancias psicomotoras, con una prevalencia general estimada de 1:10.000 niñas, según la extrapolación de algunos estudios europeos. OBJETIVOS: Realizar una revisión de la literatura sobre el síndrome de Rett y presentar una serie de casos diagnosticados en Colombia por clínica y prueba molecular. METODOLOGÍA: Se efectuó una búsqueda bibliográfica y de reportes de casos en 21 bases de datos internacionales, más de 14 revistas del área de la salud y dos motores de búsqueda generales entre 2014 y 2016. Los casos presentados fueron seleccionados de la consulta de genética médica realizada por los autores. HALLAZGOS: No se encontró ningún caso colombiano de síndrome de Rett, ni confirmado con prueba molecular en Latinoamérica. Se reporta así la primera serie de casos nacional y la mayor latinoamericana, conformada por siete pacientes con tipo clásico y tres atípicos, todas con diagnóstico molecular. CONCLUSIONES: Pese a tener una evolución clínica caracterizada, su baja prevalencia y amplio espectro clínico convierten al síndrome de Rett en un reto diagnóstico y terapéutico. La mutación c.749_750insT se reporta por primera vez, la c.473C>G por segunda en la literatura y la c.763C>T se presenta en dos pacientes con fenotipos totalmente distintos, lo que confirma la no correlación genotipo-fenotipo de la enfermedad.

SUMMARY INTRODUCTION: Rett Syndrome is a severe neurological condition and the second genetic cause of profound mental retardation in women. It is generated by mutations in the MECP2 gene and it is characterized by a loss of psychomotor gains, with an estimated overall prevalence of 1:10,000 girls, according to the extrapolation of some European studies. Objectives. To make a review of Rett Syndrome and to present a series of cases diagnosed in Colombia by clinical criteria and molecular tests. METHODOLOGY: We made a bibliographic research in 21 international databases, more than 14 health journals and two general search engines between 2014 and 2016. The cases presented were selected from the Medical Genetics consultation carried out by the authors. FINDINGS: No Colombian case of Rett Syndrome was found nor confirmed with molecular testing in Latin America. We report the first cases in Colombia and the largest in Latin America, consisting of seven patients with classic type and three with atypical type, all with molecular diagnosis. CONCLUSIONS: In spite of having a characterized clinical evolution, its low prevalence and broad clinical spectrum, make Rett Syndrome a diagnostic and therapeutic challenge. We report for the first time the mutation c.749_750insT, the c.473C> G for second time in the literature and the c.763C> T is presented in two patients with totally different phenotypes, confirming the non-correlation genotype-phenotype of the disease.

Use of Clarus Video System® in expected difficult airway in a patient with Rett syndrome. / Uso del Clarus Video System® en una vía aérea difícil en paciente con síndrome de Rett.

Difficult airway management remains one of the key points in our specialty, as the difficulty or impossibility of tracheal intubation is the main cause of morbidity/mortality attributable to anaesthesia. Rett syndrome is a severe and incapacitating neurological disease. We present the case of a 21-year-old girl affected by this syndrome, with significant psychomotor retardation and difficult airway predictors, who was scheduled to have a laparoscopic cholecystectomy under general anaesthesia. We decided on one attempt of Clarus Video System® fiberoptic intubation as primary intervention. Intubation was successfully performed with the help of this optical stylet. The use of optical stylets is gaining prominence and finding a place in the latest algorithms of difficult airway management. We highlight the growing role these devices play in managing difficult airway, therefore we review the current situation of videolaryngoscopes in the management of the predicted difficult airway.

General and oral characteristics of Rett syndrome: case report / Características gerais e orais da Síndrome de Rett: um relato de caso

Introdução: a Síndrome de Rett é uma doença neurodegenerativa que ocorre em indivíduos do sexo feminino. É a segunda causa mais frequente de deficiência mental em meninas e pode atingir diversos grupos raciais em todo o mundo. Objetivo: descrever as características gerais e orais de um indivíduo que está no terceiro estágio da doença. Relato de caso: paciente do sexo feminino portador da síndrome, com 7 anos e sete meses de idade, leucoderma, procedente de Vallo della Lucania, Salerno, Itália. O indivíduo encontra-se no terceiro estágio da síndrome, no qual são observadas características como a redução do comportamento autista, melhoras no contato visual, no sorriso e melhoras nas habilidades comunicativas. Durante o primeiro estágio da síndrome, dos seis aos dezoito meses de vida, o indivíduo se alimentava sozinho, porém ainda não andava. Já no segundo estágio a partir dos 18 meses de vida, começou a andar com a base alargada e com dois anos parou de falar. O exame genético molecular para síndrome de Rett acusou que houve uma mutação genética chamada "ad novo", ou seja, a mutação não foi de caráter hereditário. Conclusão: não há tratamento específico para a síndrome de Rett, apenas de suporte por meio da fisioterapia, hidroterapia, terapia ocupacional, musicoterapia, equoterapia, além de terapêuticas que tratam apenas alguns sintomas apresentados pela síndrome. O tratamento deve ser realizado de maneira multidisciplinar. O prognóstico consiste em acompanhar o paciente por toda a vida, tratando os sintomas por ele apresentados.(AU)

Introduction: Rett syndrome is a neurodegenerative disease that affects females of all races worldwide. It is the second most frequent cause of mental disability in girls. Objective: To describe the general and oral characteristics at stage three. Case report: A girl aged seven years and seven months, leukoderma, coming from Vallo della Lucania, Salerno, Italy was at the stage three of Rett syndrome. At the first stage, from six to eighteen months of life, the girl ate by herself, but she did not walk. At the second stage, from eighteen months of life, she started the ataxic gait and stopped talking. At the third stage, she had the reduction of the autist behavior, improved the eye contact, smile and communicative abilities. The genetic examination revealed de novo mutation, that is, without inheritance. Conclusion: Rett syndrome lacks specific treatment. Adjuvant therapies include physiotherapy, hydrotherapy, occupational therapy, music therapy, equine therapy, as well as therapies to treat some symptoms. A multidisciplinary treatment is required. The prognosis consists of following-up the individual throughout life, treating the symptoms.(AU)

Síndrome de Rett: uma revisão da literatura / Rett Syndrome: a review of the literature

Síndrome de Rett (SR) é uma desordem neurológica severa do desenvovimento, e a sua incidência é de 1:10.000 nascimentos do sexo feminino, uma das causas genéticas mais comuns de atraso mental severo em mulheres. O desenvolvimento é aparentemente normal nos primeiros seis a 18 meses de vida até que ocorre a regressão das habilidades cognitivas, sociais e motoras. A progressão e severidade da desordem são avaliadas de forma clássica e divididas em estágio I, de estagnação precoce, estágio II, rapidamente destrutivo, estágio III, pseudo estacionária, e estágio IV, de deterioração motora tardia. As mutações no gene ligado ao X metil-CpG de ligação a proteína 2 (MECP2) está presente na maioria das pacientes com a SR. O tratamento fisioterapêutico é bastante eficaz, visto que melhora ou mantém as capacidades funcionais, funções sensoriais e motoras na SR. Benefícios estes que causam grande impacto na qualidade de vida desses indivíduos com deficiências severas.

Rett syndrome (RS) is a severe neurological developmental disorder, and its incidence is 1: 10,000 female births, one of the most common genetic causes of severe mental retardation in females. The development is apparently normal in the first six to 18 months of life until regression occurs cognitive, social and motor skills. The progression and severity of the disorder are assessed and classically divided into stage I, early stagnation, stage II, rapidly destructive, stage III, stationary pseudo, and stage IV, the late motor deterioration. Mutations in the X-linked gene 2 protein binding of methyl-CpG (MECP2) is present in most patients with MR. The physical therapy is quite effective, as it improves or maintains the funcional, sensory and motor functions in SR. These benefits that greatly impact quality of life of individuals with severe disabilities.

Sindrome de Rett. Reporte de dos casos / Rett syndrome. Two Cases Report

El Síndrome de Rett es un trastorno severo del neurodesarrollo, caracterizado por un desarro- llo psicomotor aparentemente normal hasta los primeros 6 meses de vida seguido por el estancamiento y regresión del crecimiento, sistema motor, lenguaje y habilidades sociales posteriores, no asociado a una injuria cerebral por trauma, desordenes metabólicos o infec- ciones severas. A menudo se observa un com- portamiento autista en etapas tempranas: otros síntomas que acompañan este trastorno incluyen convulsiones, alteraciones respirato- rias como la hiperventilación, apnea y aerofa- gia, ataxia y estereotipas con las manos. Repre- senta la segunda causa de discapacidad inte- lectual en las mujeres. Es causado por una mutación ligada a X que codifica a la proteína ligadora de metil CpG-2 (MECP2). A continua- ción se presentan dos casos de pacientes con síndrome de Rett una de ellas con estudio molecular positivo...(AU)

[Molecular basis of Rett syndrome: A current look]. / Bases moleculares del síndrome de Rett, una mirada actual.

UNLABELLED: Rett syndrome (RS) is a neurodevelopmental disorder that exclusively affects girls, and occurs along with autism. It is very uncommon, and has five distinct forms, one classic and the others atypical, which generally compromise manual skills, language, and mobility, and widely associated with the appearance of stereotypy and early epilepsy. With the aim of updating the information about RS, a search was performed in the computer data bases of PubMed, Hinari, SCIELO and Medline, as well as consulting other web sites including OMIM, ORPHANET, GeneMap, Genetests, Proteins and Gene, using the descriptors "Síndrome de Rett", "genes y Síndrome de Rett", "Rett Syndrome gene", "Rett Syndrome", "Rett Syndrome gene therapy", and "Rett Syndrome review". Of the 1,348 articles found, 42 articles were selected, which reported 3 genes causing the syndrome: MECP2, CDKL5 and FOXG. The MECP2 gene is mutated in 80% of patients with classic RS, as well as in 40% of those affected by any of its atypical forms. RS with early epilepsy and the congenital variant are mainly due to variations in the CDKL5 and FOXG1 genes, respectively. CONCLUSIONS: The diagnosis of RS is based on clinical criteria. However, the advances in molecular biology and genetics have opened a wide range of possibilities for diagnosing the different clinical forms that could not be classified before. Molecular analysis can help confirm the clinical criteria and provided information as regards the prognosis of the patient.

Bases moleculares del síndrome de Rett, una mirada actual / Molecular basis of Rett syndrome: A current look

El síndrome de Rett (SR) es un trastorno del neurodesarrollo que afecta casi exclusivamente a niñas y cursa secundariamente con autismo. Es poco frecuente y consta de 5 formas clínicas, una clásica y el resto atípicas que comprometen de manera general la habilidad manual, el lenguaje y la motricidad amplia unida a la aparición de estereotipias y epilepsia precoz. Con el objetivo de actualizar la información sobre SR, se aplicaron los descriptores de búsqueda Síndrome de Rett, genes y «Síndrome de Rett¼, «Rett Syndrome gene¼, «Rett Syndrome¼, «Rett Syndrome gene therapy¼ y «Rett Syndrome review¼. Se investigó en los archivos digitales PubMed, Hinari, SCIELO y Medline, y se consultaron los sitios web OMIM, ORPHANET, GeneMap, Genetests, Proteins y Gene, entre otros. Entre 1.348 artículos se seleccionaron 42, los cuales reportan 3 genes causantes del síndrome: MECP2, CDKL5 y FOXG. El gen MECP2 está mutado en el 80% de los pacientes con SR clásico así como en el 40% de los afectados con alguna de sus formas atípicas. El SR con epilepsia precoz y la variante congénita se deben fundamentalmente a variaciones en los genes CDKL5 y FOXG1 respectivamente. Conclusiones: El diagnóstico del SR se basa en criterios clínicos, sin embargo, los avances en la biología molecular y en la genética en particular han abierto el abanico de posibilidades diagnósticas a las diferentes formas clínicas que antes quedaban sin clasificar, a la vez que el análisis molecular permite confirmar el criterio clínico y aportar información en cuanto al pronóstico del paciente.

Rett syndrome (RS) is a neurodevelopmental disorder that exclusively affects girls, and occurs along with autism. It is very uncommon, and has five distinct forms, one classic and the others atypical, which generally compromise manual skills, language, and mobility, and widely associated with the appearance of stereotypy and early epilepsy. With the aim of updating the information about RS, a search was performed in the computer data bases of PubMed, Hinari, SCIELO and Medline, as well as consulting other web sites including OMIM, ORPHANET, GeneMap, Genetests, Proteins and Gene, using the descriptors "Síndrome de Rett", "genes y Síndrome de Rett", "Rett Syndrome gene", "Rett Syndrome", "Rett Syndrome gene therapy", and "Rett Syndrome review". Of the 1,348 articles found, 42 articles were selected, which reported 3 genes causing the syndrome: MECP2, CDKL5 and FOXG. The MECP2 gene is mutated in 80% of patients with classic RS, as well as in 40% of those affected by any of its atypical forms. RS with early epilepsy and the congenital variant are mainly due to variations in the CDKL5 and FOXG1 genes, respectively. Conclusions: The diagnosis of RS is based on clinical criteria. However, the advances in molecular biology and genetics have opened a wide range of possibilities for diagnosing the different clinical forms that could not be classified before. Molecular analysis can help confirm the clinical criteria and provided information as regards the prognosis of the patient.

The eye-tracking of social stimuli in patients with Rett syndrome and autism spectrum disorders: a pilot study / Rastreamento do olhar para estímulos sociais em pacientes com síndrome de Rett e transtornos do espectro do autismo: estudo piloto

Objective To compare visual fixation at social stimuli in Rett syndrome (RT) and autism spectrum disorders (ASD) patients. Method Visual fixation at social stimuli was analyzed in 14 RS female patients (age range 4-30 years), 11 ASD male patients (age range 4-20 years), and 17 children with typical development (TD). Patients were exposed to three different pictures (two of human faces and one with social and non-social stimuli) presented for 8 seconds each on the screen of a computer attached to an eye-tracker equipment. Results Percentage of visual fixation at social stimuli was significantly higher in the RS group compared to ASD and even to TD groups. Conclusion Visual fixation at social stimuli seems to be one more endophenotype making RS to be very different from ASD. .

Objetivo Comparar a fixação visual em estímulos sociais em pacientes com síndrome de Rett (SR) e com transtornos do espectro do autismo (TEA). Método Fixação visual em estímulos sociais foi analisada em 14 pacientes do sexo feminino com SR (idades entre 4 e 30 anos), 11 pacientes do sexo masculino com TEA (idades entre 4 e 20 anos), e 17 crianças do sexo feminino com desenvolvimento típico (DT). Os participantes foram expostos a três figuras diferentes (duas figuras de faces humanas e uma figura contendo estímulo social e não social) apresentadas por 8 segundos cada uma no monitor de um computador acoplado a um equipamento de rastreamento de olhar. Resultados A porcentagem de fixação visual em estímulos sociais foi significativamente maior no grupo SR do que no grupo TEA e mesmo no grupo DT. Conclusão A fixação visual em estímulos sociais parece ser mais um dos endofenótipos que esclarecem as diferenças entre SR e TEA. .

Divorce in families of children with Down Syndrome or Rett Syndrome / Divórcio nas famílias com filhos com Síndrome de Down ou Síndrome de Rett

This study evaluates the impact in the stability and management of the marriage of parents of a child with Down or Rett Syndrome. Morbidity of the syndromes and the marital status of the couples before and after the birth of the affected children were considered variables. The divorce rate in families with Down syndrome was 10%, similar to the Brazilian rate population. In Rett Syndrome, the divorce rate was significantly higher, 23.5%. The higher morbidity of Rett Syndrome, and the moment of diagnosis could be relevant factors for the increased divorce rate related to this syndrome.

Este estudo buscou avaliar o impacto do nascimento de uma criança com Síndrome de Down ou Rett na estabilidade e manutenção do casamento. As variáveis consideradas foram a morbidade das síndromes e o estado marital dos casais antes e após o nascimento das crianças afetadas. A taxa de divórcio nas famílias com síndrome de Down foi de 10%, semelhante a da população brasileira. Para a Síndrome de Rett, a taxa de divórcio encontrada foi significativamente maior, 23,5%. Considera-se que tanto a maior morbidade da síndrome de Rett, bem como o momento do diagnóstico podem ser fatores relevantes para aumento de taxa de divórcio associada a esta síndrome.