Nuevas mutaciones asociadas a la enfermedad de Hirschsprung / New mutations associated with Hirschsprung disease

INTRODUCCIÓN: La enfermedad de Hirschsprung está causada por un defecto de la migración celular desde la cresta neural hasta el tracto gastrointestinal, resultando en la ausencia de neuronas en el plexo mientérico. Mutaciones en varios genes han sido asociadas a la enfermedad de Hirschsprung, la mayoría afectando a la vía del protooncogén RET. El objetivo de este estudio es la descripción de mutaciones tanto descritas como nuevas asociadas a la enfermedad de Hirschsprung, así como sus implicaciones pronósticas. MATERIAL Y MÉTODOS: Análisis retrospectivo de pacientes con enfermedad de Hirschsprung y resultados genéticos positivos desde 1970 hasta 2013. RESULTADOS: En la serie global, 21 pacientes tenían resultados genéticos positivos, 17 de ellos afectando la vía del protooncogén RET. Dos de las mutaciones son nuevas y no han sido previamente descritas en la literatura médica. CONCLUSIONES: El protooncogén RET es el principal gen asociado a la enfermedad de Hirschsprung. Todavía hay múltiples mutaciones desconocidas relacionadas con la patogenia de la enfermedad. El estudio genético del gen RET debe formar parte del estudio diagnóstico de todos los pacientes con enfermedad de Hirschsprung, así como de sus familiares de primer grado en caso de que las mutaciones estén asociadas a los síndromes MEN2A y MEN2B

INTRODUCTION: Hirschsprung disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene. Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes

[New mutations associated with Hirschsprung disease]. / Nuevas mutaciones asociadas a la enfermedad de Hirschsprung.

INTRODUCTION: Hirschsprung disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene. Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

New mutations associated with Hirschsprung disease.

INTRODUCTION: Hirschsprung Disease is caused by an impairment in cell migration from the neural crest to the gastrointestinal tract, resulting in an absence of neurons in the myenteric plexus. Many mutations in several genes have been associated to Hirschsprung disease; most of them affecting the RET proto-oncogen pathway. The purpose of this study is the description of novel and known mutations in genes associated to Hirschsprung disease and their prognostic implications. MATERIAL AND METHODS: Retrospective analysis of patients with Hirschsprung disease and positive genetic studies evaluated from 1970 to 2013. RESULTS: We found 21 positive genetic studies in the global series, 17 of them involving the RET proto-oncogene: Two of the mutations are novel and they have not been reported in the medical literature. CONCLUSIONS: The RET protooncogene is the main gene associated with Hirschsprung disease. There are still multiple unknown mutations related to the pathogenesis of the disease. The study of this gene must be part of the work-up of all patients with Hirschsprung disease, as well as their first degree relatives if the mutation is associated with MEN2A and MEN2B syndromes.

Difficulties, guidelines and review of developing an acute rejection model after rat intestinal transplantation.

Experimental small bowel transplantation (SBT) in rats has been proven to be a useful tool for the study of ischemia-reperfusion and immunological aspects related to solid organ transplantation. However, the model is not completely refined, specialized literature is scarce and complex technical details are typically omitted or confusing. Most studies related to acute rejection (AR) use the orthotopic standard, with small sample sizes due to its high mortality, whereas those studying chronic rejection (CR) use the heterotopic standard, which allows longer term survival but does not exactly reflect the human clinical scenario. Various animal strains have been used, and the type of rejection and the timing of its analysis differ among authors. The double purpose of this study was to develop an improved unusual AR model of SBT using the heterotopic technique, and to elaborate a guide useful to implement experimental models for studying AR. We analyzed the model's technical details and expected difficulties in overcoming the learning curve for such a complex microsurgical model, identifying the potential problem areas and providing a step-by-step protocol and reference guide for future surgeons interested in the topic. We also discuss the historic and more recent options in the literature.

Autoimmune cytopaenia after paediatric intestinal transplantation: a case series.

Autoimmune cytopaenia is a rare, but severe complication after solid organ transplantation. We retrospectively analysed 57 paediatric intestinal transplants performed in 49 patients between 1999 and 2009. Autoimmune cytopaenia was observed in six patients; it appeared after an average of 10 months post-transplant. Warm autoimmune haemolytic anaemia was developed in three patients, cold autoimmune haemolytic anaemia in one and two presented a mixed type. Incidence and causes for haematological cytopaenia such as the following were investigated: immunosuppression, major blood mismatch, viral infection, malignancy, passenger lymphocyte syndrome and lymphoproliferative disorders. Initial treatment included high-dose steroids, intravenous immunoglobulin, plasmapheresis and maintenance of body temperature above 37°C in those with cold autoantibodies. Inclusion of the spleen in multivisceral transplants seems to be an important risk factor. All patients, except one, relapsed after classic therapy, requiring additional treatments. Sirolimus conversion was performed in four patients. One died after infection. The immunosuppressive therapies associated with other concomitant factors, such as viral infections, lymphoproliferative disorders, graft-versus-host disease, passenger lymphocyte syndrome and the inclusion of the spleen as part of multivisceral graft seem to play an important part in the development of autoimmune processes after intestinal transplantation. Therapy is not well established, especially in those resistant to first-line treatment.