ABSTRACT
El síndrome de Silver-Russell se caracteriza por retraso del crecimiento intrauterino asimétrico, con circunferencia craneal normal, barbilla pequeña y puntiaguda, que proporciona un aspecto de rostro triangular. Puede, además, presentar asimetría corporal, entre otros. Tiene una incidencia mundial estimada de 1 en 30 000-100 000 nacimientos, aunque este número es, probablemente, subestimado. En alrededor del 60 % de los casos, se puede identificar una causa molecular y la principal es la hipometilación del alelo paterno en la región de control de impresión 1 localizado en 11p15.5-p15.4. Realizar el diagnóstico de esta entidad, excluir los diagnósticos diferenciales y conocer las correlaciones (epi)genotipo-fenotipo son necesarios para realizar el adecuado seguimiento, brindar las opciones terapéuticas disponibles y el oportuno asesoramiento genético familiar. El objetivo del presente artículo es mostrar el estado actual del síndrome de Silver-Russell, un ejemplo de trastorno de impronta genómica.
Silver-Russell syndrome is characterized by asymmetrical intrauterine growth retardation, with normal head circumference and small, pointed chin, which results in a triangular face. It can also include body asymmetry, among other characteristics. Its global incidence is estimated at 1 in 30 000-100 000 births, even though this figure may be underestimated. In approximately 60 % of cases, a molecular cause can be identified, and the main one is hypomethylation of the paternal allele at the imprinting control region 1 located at 11p15.5-p15.4. It is necessary to make the diagnosis of this entity, exclude differential diagnoses, and know (epi)genotype-phenotype correlations in order to ensure an adequate follow-up, provide available therapeutic options, and offer a timely family genetic counseling. The objective of this article is to describe the current status of the Silver-Russell syndrome, a model of genomic imprinting disorder.
Subject(s)
Humans , Male , Female , Silver-Russell Syndrome/physiopathology , Phenotype , Genomic Imprinting , Diagnosis, Differential , Silver-Russell Syndrome/diagnosis , Silver-Russell Syndrome/therapy , Fetal Growth Retardation , Genetic Counseling , GenotypeABSTRACT
Abstract Objective: To describe the results obtained in a neonatal screening program after its implementation and to assess the clinical and molecular profiles of confirmed and suspicious congenital adrenal hyperplasia cases. Methods: A cross-sectional study was conducted. Newborns with suspected disease due to high 17-hydroxyprogesterone levels and adjusted for birth weight were selected. Classical congenital adrenal hyperplasia (salt-wasting and simple virilizing forms) was diagnosed by an increase in 17-hydroxyprogesterone levels as confirmed in the retest, clinical evaluation, and genotype determined by SNaPshot and multiplex ligation-dependent probe amplification. Results: After 24 months, 15 classic congenital adrenal hyperplasia cases were diagnosed in a total of 217,965 newborns, with an estimated incidence of 1:14,531. From 132 patients, seven non-classical and 14 heterozygous patients were screened for CYP21A2 mutations, and 96 patients presented false positives with wild type CYP21A2. On retest, increased 17-hydroxyprogesterone levels were found in classical congenital adrenal hyperplasia patients and showed significant correlation with genotype-related classical genital adrenal hyperplasia. The most frequent mutations were IVS2-13A/C>G followed by gene deletion or rearrangement events in the classical form. In non-classical and heterozygous diseases, p.Val282Leu was the most common mutation. Conclusions: The results underscore the effectiveness of congenital adrenal hyperplasia neonatal screening in the public health system and indicate that the adopted strategy was appropriate. The second sample collection along with genotyping of suspected cases helped to properly diagnose both severe and milder cases and delineate them from false positive patients.
Resumo Objetivo: Descrever os resultados obtidos em um programa de triagem neonatal após sua implementação e avaliar os perfis clínicos e moleculares de casos confirmados e suspeitos de hiperplasia adrenal congênita. Métodos: Foi feito um estudo transversal. Recém-nascidos com suspeita da doença devido aos altos níveis de 17-alfa-hidroxiprogesterona e ajustados pelo peso ao nascer foram selecionados. A hiperplasia adrenal congênita clássica (forma perdedora de sal e forma virilizante simples) foi diagnosticada por um aumento nos níveis de 17-alfa-hidroxiprogesterona confirmado no reteste, avaliação clínica e genótipo determinado com o uso do ensaio SNaPshot e amplificação multiplex de sondas dependente de ligação. Resultados: Após 24 meses, 15 casos clássicos de hiperplasia adrenal congênita foram diagnosticados em 217.965 recém-nascidos, com uma incidência estimada de 1:14.531. De 132 pacientes, sete não clássicos e 14 heterozigotos foram submetidos à triagem para mutações no gene CYP21A2 e 96 pacientes apresentaram resultados falso-positivos com CYP21A2 do tipo selvagem. No reteste, níveis aumentados de 17-alfa-hidroxiprogesterona foram encontrados em pacientes com hiperplasia adrenal congênita clássica e mostraram correlação significativa com HAC clássica relacionada ao genótipo. As mutações mais frequentes foram IVS2-13A/C>G, seguidas de deleção gênica ou eventos de rearranjo na forma clássica. Em casos de doenças não clássicas e heterozigose, a mutação p.Val282Leu foi a mais comum. Conclusões: Os resultados ressaltam a eficácia da triagem neonatal para a hiperplasia adrenal congênita no sistema público de saúde e indicam que a estratégia adotada foi adequada. A segunda coleta de amostras, juntamente com a genotipagem dos casos suspeitos, ajudou a diagnosticar adequadamente os casos graves e mais leves e diferenciá-los de pacientes com resultado falso-positivo.
Subject(s)
Humans , Male , Female , Infant, Newborn , Steroid 21-Hydroxylase/blood , Neonatal Screening/methods , Adrenal Hyperplasia, Congenital/diagnosis , 17-alpha-Hydroxyprogesterone/blood , Phenotype , Brazil/epidemiology , Biomarkers/blood , Incidence , Cross-Sectional Studies , Adrenal Hyperplasia, Congenital/genetics , Adrenal Hyperplasia, Congenital/epidemiology , Genotype , MutationABSTRACT
Resumen Las cardiopatías familiares son un grupo de enfermedades con alta heterogeneidad clínica y genética. Debido a que pueden heredarse y a su asociación con la muerte súbita, se recomienda efectuar un estudio clínico y genético del individuo afectado y su familia a través de una unidad especializada. Con la implementación de la secuenciación masiva se ha facilitado el acceso a los estudios genéticos en la práctica clínica de forma más rutinaria. Sin embargo, dada la gran cantidad de información obtenida se hacen necesarios el análisis y la interpretación adecuada de los resultados para garantizar un diagnóstico correcto. Este nuevo modelo de medicina amplía nuestra comprensión sobre estas patologías, gracias a que optimiza el diagnóstico, da una mejor aproximación pronóstica de los pacientes e identifica individuos asintomáticos en riesgo. Este artículo pretende realizar una revisión de la arquitectura genética de las enfermedades cardíacas hereditarias y proporcionar un enfoque práctico acerca de la utilidad de la Medicina genómica en el diagnóstico, la estratificación del riesgo y el estudio familiar en pacientes con este tipo de patologías.
Abstract The familial heart diseases are a group of diseases with high clinical and genomic heterogeneity. As they can be inherited and are associated with sudden death, it is recommended to perform a clinical and genetic study of the individual affected, as well as the family, in a specialised unit. The implementation of massive sequencing has meant that access to genetic studies is available in the most routine clinical practice. However, due to the large amount of information obtained, the results have to analysed and interpreted to ensure a correct diagnosis. This new medicine model widens the understanding of these diseases, as due to the diagnosis being optimised, it provides a more accurate prognosis for the patients, and identifies asymptomatic individuals at risk. A review is presented on the genetic architecture of heritable heart disease and provides a practical approach on the usefulness of Genomic Medicine in the diagnosis, risk stratification, and the familial study in patients with these types of heart diseases.
Subject(s)
Humans , Death, Sudden, Cardiac , Cardiomyopathies , Phenotype , Whole Genome Sequencing , GenotypeABSTRACT
Dissecting the genetic basis of adaptive traits is key to our understanding of evolutionary processes. A major and essential step in the study of evolutionary genetics is drawing link between genotype and phenotype, which depends on the difficult process of defining the phenotype at different levels, from functional to organismal. Visual pigments are a key component of the visual system and their evolution could also provide important clues on the evolution of visual sensory system in response to sexual and natural selection. As a system in which genotype can be linked to phenotype, I will use visual pigments and color vision, particularly in birds, as a case of a complex phenotype. I aim to emphasize the difficulties in drawing the genotype-phenotype relationship for complex phenotypes and to highlight the challenges of doing so for color vision. The use of vision-based receiver models to quantify animal colors and patterns is increasingly important in many fields of evolutionary research, spanning studies of mate choice, predation, camouflage and sensory ecology. Given these models impact on evolution and ecology, it is important to provide other researchers with the opportunity to better understand animal vision and the corresponding advantages and limitations of these models.
Entender la base genética de los rasgos adaptativos es un paso crítico en el estudio de los procesos evolutivos. Para estudiar la conexión entre genotipo y fenotipo es importante definir el fenotipo a diferentes niveles: desde las proteínas que se construyen con base en un gen, hasta las características finales presentes en un organismo. Las opsinas y los fotopigmentos son elementos primordiales de la visión y entender cómo han evolucionado es fundamental en el estudio de la visión en los animales como un caracter derivado de selección natural o sexual. Este artículo se enfoca en este sistema, en el que se pueden conectar genotipo y fenotipo, como ejemplo de fenotipo complejo para ilustrar las dificultades de establecer una relación clara entre genotipo y fenotipo. Adicionalmente, este artículo tiene como objetivo discutir el funcionamiento del sistema de fotorrecepción, con énfasis particular en las aves, con el fin de enumerar varios factores que deben ser tenidos en cuenta para predecir cambios en la visión a partir del estudio de los fotopigmentos. Dado que los modelos basados en la visión de aves son cada vez más usados en diversas áreas de la biología evolutiva tales como: selección de pareja, depredación y camuflaje; se hace relevante entender los fundamentos y limitaciones de estos modelos. Por esta razón, en este artículo discuto los detalles y aspectos prácticos del uso de los modelos de visión existentes para aves, con el fin de facilitar su uso en futuras investigaciones en diversas áreas de evolución.
ABSTRACT
It has been suggested that the R92Q mutation of the tumour necrosis factor receptor superfamily 1A (TNFRS1A) gene may be implicated in different inflammatory disorders. The aim of this study was to establish the role of this mutation as a determinant of Crohn`s disease (CD) susceptibility and/or clinical phenotype. One hundred and sixty-five CD patients and 203 healthy controls were prospectively included. The frequency of individuals carrying the R92Q mutation was similar between CD patients (4.24 percent) and controls (4.43 percent) (OR: 0.95; 95 percent CI = 0.34-2.62). In the genotype-phenotype evaluation, the univariate analysis showed that extra-intestinal manifestations were positively associated with the presence of R92Q mutation (p = 0.025; OR: 5.56; 95 percent CI = 1.04-29.6). In the multivariate analysis, presence of R92Q mutation was independently associated to extra-intestinal manifestations of CD, specially cutaneous manifestations (p = 0.02; OR: 5.17, 95 percent CI = 1.07-24.8). The R92Q mutation of TNFRSF1A gene is not a determinant of CD susceptibility, but contributes to the appearance of extra-intestinal manifestations of the disease.
Se ha sugerido que la mutación R92Q del gen de la super-familia del receptor del factor de necrosis tumoral 1A (TNFRS1A) podría estar relacionada con diversos trastornos inflamatorios. El objetivo de este estudio fue determinar el papel de esta mutación como factor determinante de la susceptibilidad y/o fenotipo clínico de la enfermedad de Crohn (EC). Ciento sesenta y cinco pacientes con EC y 203 controles sanos fueron incluidos de manera prospectiva. La frecuencia de individuos portadores de la mutación R92Q fue similar entre los pacientes con EC (4,24 por ciento) y los controles (4,43 por ciento) (OR: 0,95; 95 por ciento IC = 0,34-2,62). En la evaluación genotipo-fenotipo, el análisis univariado indicó que las manifestaciones extra-intestinales estaban relacionadas con la presencia de la mutación R92Q (p = 0,025; OR: 5,56; 95 por ciento IC = 1,04-29,6). En el análisis multivariado, la presencia de la mutación R92Q estuvo relacionada de manera independiente con las manifestaciones extra-intestinales de la EC, especialmente manifestaciones cutáneas (p = 0,02; OR: 5,17, 95 por ciento IC = 1,07-24,8). La mutación R92Q del gen TNFRSF1A no es un factor determinante de susceptibilidad a EC, pero contribuye a la aparición de manifestaciones extra-intestinales de la enfermedad.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Crohn Disease/complications , Crohn Disease/genetics , Receptors, Tumor Necrosis Factor, Type I/genetics , Inflammatory Bowel Diseases/genetics , Skin Diseases/etiology , Case-Control Studies , Follow-Up Studies , Phenotype , Genotype , MutationABSTRACT
El síndrome de Down, es la causa más frecuente de discapacidad intelectual, fue descrito por primera vez en el año 1886, durante una era de grandes cambios en el conocimiento de la genética y la evolución. Ocurre con una frecuencia de 1 por cada 700 nacidos vivos. En muchos casos la historia de la investigación en el síndrome de Down cursa paralela a la historia de la genética humana y ha sido fuente de grandes progresos en esta ciencia. En esta revisión se describe la interrelación entre los avances del conocimiento de la genética y el conocimiento del síndrome de Down tomando en consideración el impacto del descubrimiento de su etiología realizado en 1959 por Jerone Lejeune. Con motivo de la celebración de los 50 años de este acontecimiento, se escogió este descubrimiento como marcador de división cronológica de las etapas de producción del conocimiento sobre el síndrome, obteniéndose la era pre y pos-Lejeune, desde su descripción inicial al presente y sobre la base de esta perspectiva histórica se especula brevemente acerca del futuro de la investigación en el síndrome de Down
Down syndrome, is the most common cause of intellectual disabilities, it was first described in 1866, during an era of great change in understanding of genetics and evolution. It occurs in about I of every 700 newborns. In many instances, The history of research on Down syndrome courses parallels with the history of human genetics and it has inspired progress in human genetics. In this revision, it is described the interplay between advances in the understandins of genetics and the understanding of the Down syndrome and it was considered the finding of its etiology by Jerone Lejeune in 1959, as the index, Fifty years the discovery of the origin of the Down syndrome, it has been utilized for the division of two eras in the generation of knowledge in Down syndrome, the pre and the post-Lejeune era, from its initial description to the present, and on the basis of this historical perspective, speculate briefly about the future of research on Down syndrome
Subject(s)
Humans , Male , Female , Intellectual Disability/etiology , Down Syndrome/etiology , Down Syndrome/history , AneuploidyABSTRACT
BACKGROUND: Rett syndrome (RS) is a severe neurodevelopmental X-linked dominant disorder caused by mutations in the MECP2 gene. PURPOSE: To search for point mutations on the MECP2 gene and to establish a correlation between the main point mutations found and the phenotype. METHOD: Clinical evaluation of 105 patients, following a standard protocol. Detection of point mutations on the MECP2 gene was performed on peripheral blood DNA by sequencing the coding region of the gene. RESULTS: Classical RS was seen in 68 percent of the patients. Pathogenic point mutations were found in 64.1 percent of all patients and in 70.42 percent of those with the classical phenotype. Four new sequence variations were found, and their nature suggests patogenicity. Genotype-phenotype correlations were performed. CONCLUSION: Detailed clinical descriptions and identification of the underlying genetic alterations of this Brazilian RS population add to our knowledge of genotype/phenotype correlations, guiding the implementation of mutation searching programs.
INTRODUÇÃO: A síndrome de Rett é uma grave doença do neurodesenvolvimento ligada ao X dominante, causada por mutações no gene MECP2. OBJETIVOS: Identificar mutações de ponto no gene MECP2 e estabelecer uma correlação entre as principais mutações encontradas e o fenótipo. MÉTODO: Avaliação clínica de 105 pacientes, seguindo um protocolo estabelecido. A identificação de mutações de ponto foi realizada em DNA de sangue periférico por sequenciamento da região codificante do gene amplificada por PCR. RESULTADOS: Em 68 por cento dos pacientes observou-se o quadro clássico da síndrome. Mutações de ponto patogênicas foram encontradas em 64,1 por cento dos pacientes e em 70,42 por cento das pacientes com o quadro clássico. Quatro novas variações de seqüência foram identificadas e sua natureza sugere patogenicidade. Correlações genótipo-fenótipo foram estabelecidas. CONCLUSÃO: Descrições clínicas detalhadas desta população brasileira de pacientes acrescenta conhecimento às correlações genótipo-fenótipo nesta grave condição, que podem auxiliar na implantação de programas de triagem de mutações.
Subject(s)
Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Young Adult , DNA , Genetic Association Studies , /genetics , Point Mutation/genetics , Rett Syndrome/genetics , Brazil , Polymerase Chain Reaction , Young AdultABSTRACT
Objetivo: Determinar si existe asociación entre genes implicados en la codificación de PBP2a con la expresión fenotípica de resistencia a meticilina en cepas de Staphylococcus spp. Diseño: Descriptivo Transversal. Metodologias: e determinó la resistencia y sensibilidad de 67 aislamientos, mediante pruebas fenotípicas (difusión en disco, concentración inhibitoriamínima CIM, producción de PBP2a y pruebas genotípicas para detectar los genes mecA y sus reguladores mecR1 y mecI por Reacción em Cadena de la Polimerasa (PCR). Resultados: De 9 cepas de S. aureus resistentes por difusión en disco solo 1 fue sensible por CIM. De 7 cepas resistentes por CIM, fueron sensibles por difusión en disco. Por el contrario las 7 cepas de Staphylococcus coagulasa negativo sensibles por difusión en disco fueron resistentespor CIM.En cuanto a la prueba de producción de PBP2a, los resultados fueron discordantes con la prueba de difusión en disco en 20..
Objective: Determining the association between genes involved in the codifi cation of Penicillin Binding Proteins 2A (PBP2A) with the phenotypic expression of methicillin resistance in Staphylococcus spp. Strains Design: Descriptive cross sectional Methodology: The sensitivity of 67 isolates was determined by means of a phenotypic test (disk diffusion, minimum inhibitory concentration CIM, production of PBP2a) and genotype tests to detect the mecA gene and its regulatory mecR1 and mecI by Polymerase Chain Reaction (PCR). Results: From 9 S. aureus resistant strains by disk diffusion 1 was sensitive by CIM, 7 CIM resistant strains were sensitive by disk diffusion. The 7 coagulase negative (CNS) sensitive strains by disk diffusion were resistant by CIM. By production of PBP2a, the results were discordant with the disk diffusion test in 20% and 34%with CIM. The genotype, reveals that, from 60 S.aureus strains 10(17%), and 7 S. coagulase negative strains 4 (57%) carry the mecA gene. From 10 S. aureus mecA positive strains, 5 carry the mecR1 gene and 7 carry the mecI gene. Of the 4 strains of S.coagulase negative mecA positive 2 carry the mecR1 and 2 carry the mecI gene. Conclusion: There is no association between genotype and phenotype in Staphylococcus spp. methicillin resistant strains, since, the resistance is due to many factors that the classical phenotypic test does not include.