Consenso de la Rama de Genética de la Sociedad Chilena de Pediatría sobre las anomalías congénitas de mal pronóstico vital (ACMPV): Genetics Consensus Committee / Congenital anomalies of poor prognosis

Introducción: La rama de genética de la Sociedad Chilena de Pediatría, en relación con el proyecto de ley que regula la despenalización de la interrupción voluntaria del embarazo en 3 causales, centrándose en la segunda causal que considera al «embrión o feto que padezca una alteración estructural congénita o genética incompatible con la vida extrauterina¼, se reunió para discutir conforme a la evidencia científica qué anomalías congénitas (AC) podrían ser incluidas en el proyecto de ley. Metodología: Los expertos en genética clínica se centraron en 10 AC. Se efectuó revisión bibliográfica y una reunión extraordinaria para discutirla. Resultados: Se acordó no emplear el término «incompatible con la vida extrauterina¼, pues existen excepciones de sobrevidas más prolongadas y cambiar por «anomalía congénita de mal pronóstico vital (ACMPV)¼. Se evaluaron 10 AC: defectos graves de cierre del tubo neural: anencefalia, iniencefalia y craneorraquisquisis, hipoplasia pulmonar, feto acardio, ectopia cordis, triploidía no mosaico, complejo limb body wall, anomalía body stalk, trisomía 13, trisomía 18 y agenesia renal bilateral. Se analizaron los hallazgos sobre prevalencia, historia natural, métodos diagnósticos prenatales, sobrevida, casos descritos de sobrevida prolongada. Para catalogarlas como ACMPV se consideraron: sobrevida posnatal, existencia de tratamientos y evolución posterior e historia natural sin intervenciones. Conclusión: Las ACMPV incluidas serían: anencefalia, hipoplasia pulmonar severa, feto acardio, ectopia cordis cervical, triploidía no mosaico, complejo limb body wall, anomalía body stalk, trisomía 13 no mosaico, trisomía 18 no mosaico y agenesia renal bilateral. Se requiere para el diagnóstico que toda mujer gestante tenga acceso a evaluaciones ecográficas de anatomía fetal, y en ocasiones a resonancia magnética y estudios citogenéticos y moleculares.

Introduction: The Genetic Branch of the Chilean Society of Paediatrics, given the draft Law governing the decriminalisation of abortion on three grounds, focusing on the second ground, which considers the "embryo or foetus suffering from a congenital structural anomaly or a genetic disorder incompatible with life outside the womb", met to discuss the scientific evidence according to which congenital anomalies (CA) may be included in this draft law. Methodology: Experts in clinical genetics focused on 10 CA, reviewed the literature evidence, and met to discuss it. Results: It was agreed not to use the term "incompatible with life outside the womb", as there are exceptions and longer survivals, and change to "congenital anomaly of poor prognosis (CAPP)". Ten CA were evaluated: serious defects of neural tube closure: anencephaly, iniencephaly and craniorachischisis, pulmonary hypoplasia, acardiac foetus, ectopia cordis, non-mosaic triploidy, "limb body wall" complex, "body stalk" anomaly, trisomy 13, trisomy 18, and bilateral renal agenesis. Findings on the prevalence, natural history, prenatal diagnostic methods, survival, and reported cases of prolonged survival were analysed. Post-natal survival, existence of treatments, and outcomes, as well as natural history without intervention, were taken into account in classifying a CA as a CAPP. Conclusion: A CAPP would be: anencephaly, severe pulmonary hypoplasia, acardiac foetus, cervical ectopia cordis, non-mosaic triploidy, limb body wall complex, body stalk anomaly, non-mosaic trisomy 13, non-mosaic trisomy 18, and bilateral renal agenesis. For their diagnosis, it is required that all pregnant women have access to assessments by foetal anatomy ultrasound and occasionally MRI, and cytogenetic and molecular testing.

Cáncer hereditario de colon: Aportes del diagnóstico genético molecular / Molecular and genetic studies for hereditary colon cancer in two patients and their families

Background: About 30 percent of cases of colon cancer (CC) have a family history of CC, and only 5 percent are hereditary forms. Hereditary forms have an increased risk of CC and other tumors. Aim: To report the molecular and genetic study in two families with hereditary CC. Material and Methods: Molecular analysis of the adenomatous polyposis coli (APC) gene of familial adenomatous polyposis (FAP), was done in a patient with multiple benign polyps and his children. Molecular analysis was performed for MLH1 gene mutation of hereditary non-polyposis colon cancer (HNPCC) in an asymptomatic patient with family history of multiple cancers and his mother with a confrmed mutation in the MLH1 gene. Results: The patient with FAP had an insertion of 17 base pairs in exon 9 of the APC gene and two of his children had the same mutation. The patient with history of HNPCC did not have the family mutation on MLH1. Conclusions: In the case of FAP, molecular study was performed in his children since manifestations in carriers of the mutation may begin in childhood. If the second patient would have had the mutation, the study of his children could have been postponed until the age of 18, when the risk for CC is increased.

Marcadores genéticos en hipertensión esencial / Genetic markers in essential hypertension

Essential hypertension (HTA) is a multifactorial disease and in Chile, its prevalence is 33.7 percent. There is a genetic predisposition to develop hypertension, whose magnitude is approximately 30 to 50 percent. At present, some factors are known to increase the risk for cardiovascular disease, but widely accepted biomarkers for screening are missing. The frst studies that looked for candidate genes have focused on the reninangiotensin - aldosterone, aducina, adrenoreceptors ß, G protein subunits, G protein signaling regulators, kinases associated with G proteins and Rho kinases. Studies of DNA sequencing, search for polymorphisms and variants through single nucleotide polymorphisms, have been used to seek partnerships with complex or multifactorial diseases, like HTA. Examples of these are: components of collagen proteins, genes related to cell myocardial proteins belonging to cytochrome P450 and growth factors, among others. It is still unlikely to count in a near future with a universal marker. Most probably, a series of markers that confer susceptibility to a specifc individual will have to be used in prevention programs or personalized therapy.

Hipertensión arterial infantil de origen monogénico / Hypertension Infant monogenic origin

La hipertensión arterial (HTA) es una patología frecuente en el adulto, en cambio, en pediatría es una patología subdiagnosticada y con una prevalencia del 1 al 2 por ciento. La hipertensión arterial de origen monogénico, representa a menos del 1 por ciento del total, sin embargo es importante su diagnóstico debido a que puede tener riesgo de recurrencia en la familia y ser transmitida a la descendencia. En esta revisión se describen los elementos de sospecha de HTA de origen monogénico, las causas principales, etiopatogenia molecular, clínica, técnicas diagnósticas, modos de herencia y tratamientos. Además se comenta el estado del arte sobre los genes candidatos en la HTA esencial. Conclusión: la HTA de origen monogénico es una señal de alerta de una condición subyacente, la historia personal, los antecedentes familiares y los exámenes de laboratorio, condicionarán el diagnósitco y el asesoramiento genérico para el paciente, como también una búsqueda dirigida en sus familiares.