Résumé
El desarrollo de la Genética Humana ha puesto a disposición de la Medicina potentes recursos para Investigar los cambios en el material genético subyacentes a diversas enfermedades en pacientes individuales y sus familias. Semejante capacidad diagnóstica suele exceder en mucho a la capacidad de brindar una terapéutica específica, por lo que su utilidad médica reside en el perfeccionamiento del diagnóstico, la estimación del pronóstico clínico, y el cálculo del riesgo de recurrencia para futuros hermanos e hijos de un paciente dado; el paciente y/o su familia, por su parte, suelen buscar en el diagnóstico genético una certeza que les permita limitar su ansiedad. En Pediatría, el consenso mayoritario es que en los niños se justifica la investigación genética diagnóstica, que la investigación predictiva puede hacerse si la afección investigada permite una intervención médicamente beneficiosa durante la niñez, y que la del estado de portación debe diferirse hasta que el paciente alcance un cierto grado de madurez y competencia. El propósito de este trabajo es plantear los aspectos bioéticos y legales relacionados con la investigación de una familia que está segregando una mutación para adrenoleucodistrofia ligada al X, en la que por diversas circunstancias se estudió a menores de edad. Se discute la naturaleza de la enfermedad, el hecho de que tres de los individuos estudiados eran menores de edad, el rol proactivo de los padres en el proceso de toma de decisiones conducente a la investigación de tales miembros, y la existencia de un marco legal específico para la intervención.
Human Genetics development has furnished Medicine with potent resources to investigate changes in genetic material underneath a host of diseases in individual patients and their families. Such a diagnostic capability usually exceeds greatly the capability of specific therapeutic intervention, so its medical usefulness lies in perfecting the diagnosis, estimating the clinical prognosis and calculating the risk of recurrence among future sibs and children of a certain patient; on the other hand, the patient and/or his/her family usually look into genetic diagnosis for a certainty that enables them to limit their anxiety. In Pediatrics, the majority consensus is that children may be submitted to genetic research with diagnostic purposes, that predictive research might be done if the disease in question is amenable of a medically beneficial intervention during childhood, and that carrier state determination should be deferred until the patient reaches maturity and competence. The goal of this work is to review bioethical and legal aspects of the genetic investigation of a Tucumanian family segregating a mutation for X-linked adrenoleukodystrophy, in which for various reasons underage individuals were studied. We discuss the nature of the disease, the fact that three of the research subjects were underage, the proactive role of the family in the decision-making process leading to research those members, and the local existence of a specific legal frame for this intervention.
O desenvolvimento da genética humana tem dotado de recursos poderosos à medicina para pesquisar mudanças no material genético, subjacentes a diversas doenças nos pacientes e nas famílias. Essa capacidade de diagnóstico é muitas vezes maior do que a capacidade de fornecer uma terapia específica; portanto, sua utilidade médica está no aperfeiçoamento do diagnóstico, a estimativa do prognóstico clínico e o cálculo do risco de recorrência para irmãos e filhos de determinado paciente. O paciente e sua família tendem a visar no diagnóstico uma segurança genética que lhes permita limitar sua ansiedade. Em Pediatria, o consenso da maioria justifica a pesquisa genética diagnóstica em crianças, assinala que a pesquisa preditiva pode levar-se a cabo se a condição permite uma intervenção medicamente benéfica durante a infância e afirma que la solução ao estado de portador deverá pospor-se até que o paciente atinge determinada maturidade e competência. O objetivo deste trabalho é apresentar aspectos bioéticos e jurídicos relacionados com a pesquisa em de uma família que está segregando uma mutação para adrenoleucodistrofia ligada ao cromossoma X, na que por diversas razões foram estudados menores.Discute-se a natureza da doença, o fato que três dos indivíduos foram menores, o papel proativo dos pais no processo decisório -em quanto à pesquisa desses membros- e a existência de um quadro jurídico específico para a intervenção.
Sujets)
Humains , Bioéthique , Pédiatrie , Législation , Recherche génétiqueRésumé
Objective. To determine the pattern of deletions of the dystrophin gene, the major class of mutations among the Duchenne and Becker muscular dystrophy patients of eastern India and to analyze the carrier frequency of the female members of the proband’s family. Methods. Deletional mutations occurring in patients have been characterized by multiplex polymerase chain reaction. Carrier state of mothers and sisters of probands were analyzed by either of two methods: 1) typing polymorphic short tandem repeat markers in or around the regions of deletion, by radioactive polymerase chain reaction and 2) quantitative real time amplification of the region of deletion. Results. Deletions were detected in 67 (62.04%) out of 108 male patients, about 76.12% of these being localized in the central hot spot region of the gene, i.e., between exon 42 to exon 53 and 17.91% at the proximal hot spot i.e., between exon 1 to exon 20. In the present study were found 43 types of deletions, out of which 25 (58%) were new deletions, which were not described earlier among the Indian patients. Distribution pattern of deletions in different hot spot regions has been compared with that of other countries and statistical analysis reveals significant difference between countries (p<0.001). Correlation of the pattern of deletion with clinical phenotype of patients has been discussed. Interesting case of germline mosaicism and its implications in counseling has also been discussed. Conclusion. About half the mothers of affected probands were not carriers of the deletion, underscoring the need to use real time techniques for carrier detection.