Abstract: In the framework of the vaccination campaign against the SARS-CoV-2 virus, the Chilean Ministry of Health requested advice from the Genetics Branch of the Chilean Society of Pediatrics, to define the level of prioritization for people with Down Syndrome . A panel of geneticists worked on the development of this consensus, in which not only patients with Down syndrome were included, but the search was extended to patients with other types of disabilities, in both pediatric and adult ages in or der to contribute to the development of public health measures against the COVID-19 pandemic. The consensus concludes that, given the prevalence of comorbidities associated with Down syndrome, the higher incidence of cases with severe COVID-19 in this population group and a higher mortality, individuals with trisomy 21 should be considered as a high-risk population, and therefore, vaccina tion against SARS-CoV-2 should have a high priority for all people with Down syndrome regardless of their age (except for the age limit established by the clinical trials of each vaccine), and should be preceded only by the groups of health personnel and adults aged > 60-65 years. Likewise, this group of experts urges health authorities to include people with intellectual disabilities and related conditions as a priority population (other chromosomal abnormalities other than Down syndrome, intellectual disability, congenital anomalies and conditions that cause disability with microcephaly), as well as the caregivers of people with this type of conditions. Vaccination in children with this type of disorders should be considered as part of the first priority group, once safe vaccines against SARS-CoV-2 are available for use in children and adolescents.

Resumen: En el marco de la campaña de vacunación contra el virus SARS-CoV-2, el Ministerio de Salud de Chile solicitó asesoría a la de Rama de Genética de la Sociedad Chilena de Pediatría, para definir el nivel de priorización para pacientes con Síndrome de Down. Un panel de Genetistas trabajó en el de sarrollo de este consenso, en el cual se incluyeron no solo los pacientes con Síndrome de Down, sino que se amplió la búsqueda a pacientes con otros tipos de discapacidades, en edades tanto pediátricas como adultas con el fin de aportar al desarrollo de medidas de salud pública frente a la pandemia de la COVID-19. El consenso concluye que, dados los antecedentes epidemiológicos de comorbilidades asociadas al Síndrome de Down, la mayor incidencia de casos de infección grave en este grupo de la población y mayor mortalidad, se debe considerar a los individuos con Trisomía 21 como una pobla ción de alto riesgo, y por ende, la vacunación contra SARS-CoV-2 debe tener prioridad alta para to das las personas con Síndrome de Down independiente de su edad (salvo el límite establecido por los ensayos clínicos de cada vacuna), debiendo ser precedidas solo por los grupos de personal de la salud y adultos con > 60-65 años. Así mismo este grupo de expertos insta a las autoridades de salud a incluir como población prioritaria a las personas con discapacidad intelectual y condiciones relacionadas (otras anomalías cromosómicas diferentes a Síndrome de Down, discapacidad intelectual, anomalías congénitas y condiciones causantes de discapacidad con microcefalia), así como a los cuidadores de personas con este tipo de patologías. La vacunación en niños con este tipo de enfermedades debie ra considerarse como parte del primer grupo de prioridad, una vez se disponga de vacunas contra SARS-CoV-2 seguras para ser empleadas en los niños, niñas y adolescentes.

ABSTRACT Introduction: The objectives of prenatal diagnosis of fetal malformations are to offer the patient and her family the proper counseling, identify those conditions that benefits of prenatal therapy and to coordinate the referral to tertiary centers to improve neonatal survival. Our hospital counts with a multidisciplinary team who evaluate the patients together. The objective of this study is to describe our experience as a referral center in prenatal diagnosis, management and neonatal outcomes in Santiago de Chile. Methods: Retrospective and descriptive study. Patients registered in our prenatal diagnosis database between September 2010 and July 2019 were included. Clinical files were reviewed for neonatal outcomes. Outcomes: 404 patients with congenital malformations or aneuploidy markers were evaluated. The average gestational age of the evaluation was 29 weeks. Median gestational age to delivery was 37 weeks plus 6 days. 78% of livebirth, 12% fetal demise and 10% of neonatal death were obtained. The most frequent fetal malformations were cardiovascular, central nervous system, fetal hydrops, extremities, abdominal wall defects and urinary system. Fetal karyotype was performed in 232 patients; 61% normal karyotype, 12.5% trisomy 21, 8% trisomy 18, 4% trisomy 13, 4% monosomy X, 4% others. We also analyze the patients who agreed to termination of pregnancy according to Chilean legislation. Conclusion: We highlight the importance of referral of patients with suspected fetal malformations to tertiary centers for an adequate evaluation by a multidisciplinary team of specialists, to improve the survival and neonatal outcome.

RESUMEN Introducción: El diagnóstico prenatal de anomalías congénitas tiene como objetivo ofrecer consejería apropiada, identificar aquellas patologías que se benefician de terapia fetal y coordinar la derivación de estas pacientes a centros terciarios para un óptimo manejo perinatal. Para el diagnóstico y manejo de las anomalías congénitas en el Hospital Dr. Sótero Del Río contamos con un equipo multidisciplinario. El objetivo de este estudio es describir nuestra experiencia como centro de referencia en Santiago de Chile en relación al diagnostico prenatal de malformaciones congénitas, estudio genético prenatal y resultados perinatales. Métodos: Estudio retrospectivo y descriptivo. Se incluyó a las pacientes registradas en las bases de datos ecográficas entre 2010 y 2019 del Hospital Dr. Sotero del Rio. Se revisaron fichas clínicas para evaluación y seguimiento postnatal. Resultados: Se evaluaron 404 pacientes con sospecha de malformaciones congénitas o marcadores de aneuploidías. La edad gestacional media de la evaluación fue 29 semanas (14-38 semanas). La mediana de la edad gestacional al parto fue 37.6 semanas (20-41 semanas). Se obtuvo un 78% de recién nacidos vivos, 12% óbitos fetales y 10% mortineonatos. Las malformaciones más frecuentes fueron cardiovasculares, sistema nervioso central, hidrops, extremidades, abdomen y genitourinario. Se realizo el estudio genético en 232 pacientes; 61% resultado normal, 12.5% trisomía 21, 8% trisomía 18, 4% trisomía 13, 4% XO, 4% otras. Se analizaron las pacientes que se acogieron a la ley de interrupción voluntaria del embarazo. Conclusión: Destacamos la importancia de derivación a centros de referencia de pacientes con sospecha de malformaciones congénitas para un adecuado diagnostico prenatal, ofrecer un manejo con equipo multidisciplinario y así mejorar los resultados neonatales.

OBJETIVO: O uso clínico de técnicas baseadas em microarrays para a análise de transtornos de desenvolvimento tem surgido durante a última década. Assim, o microarray cromossômico tem sido posicionado como um teste de primeiro nível clínico. Relatamos a primeira experiência em uma coorte chilena. MÉTODOS: Pacientes chilenos com atraso de desenvolvimento e anomalias congênitas foram estudados com um microarray de alta densidade (CytoScan(tm) HD Array, Affymetrix, Inc., Santa Clara, CA, EUA). Pacientes tiveram estudos citogenéticos anteriores, ou um resultado normal ou de uma anomalia não bem caracterizada. RESULTADOS: Foram analisados 40 pacientes selecionados por dois ou mais critérios, incluindo: anomalias congênitas maiores, dismorfismo facial, atraso de desenvolvimento e deficiência intelectual. Uma variante do número de cópia (CNV) foi encontrada em 72,5% dos pacientes, enquanto que uma CNV patogênica foi encontrada em 25% dos pacientes e uma CNV de significado clínico incerto foi encontrada em 2,5% dos pacientes. CONCLUSÕES: A análise cromossômica microarray é uma ferramenta útil e poderosa em transtornos de desenvolvimento, permite um diagnóstico preciso, melhora a taxa de diagnóstico e descobre novas etiologias. O custo mais elevado é uma limitação para um uso difundido em nossa realidade.

OBJECTIVES: Clinical use of microarray-based techniques for the analysis of many developmental disorders has emerged during the last decade. Thus, chromosomal microarray has been positioned as a first-tier test. This study reports the first experience in a Chilean cohort. METHODS: Chilean patients with developmental disabilities and congenital anomalies were studied with a high-density microarray (CytoScan(tm) HD Array, Affymetrix, Inc., Santa Clara, CA, USA). Patients had previous cytogenetic studies with either a normal result or a poorly characterized anomaly. RESULTS: This study tested 40 patients selected by two or more criteria, including: major congenital anomalies, facial dysmorphism, developmental delay, and intellectual disability. Copy number variants (CNVs) were found in 72.5% of patients, while a pathogenic CNV was found in 25% of patients and a CNV of uncertain clinical significance was found in 2.5% of patients. CONCLUSION: Chromosomal microarray analysis is a useful and powerful tool for diagnosis of developmental diseases, by allowing accurate diagnosis, improving the diagnosis rate, and discovering new etiologies. The higher cost is a limitation for widespread use in this setting.

BRCA1 gene mutations account for nearly all families with multiple cases of both early onset breast and/or ovarian cancer and about 30% of hereditary breast cancer. Although to date more than 1,237 distinct mutations, polymorphisms, and variants have been described, several mutations have been found to be recurrent in this gene. We have analyzed 63 Chilean breast/ovarian cancer families for eighteen frequent BRCA1 mutations. The analysis of the five exons and two introns in which these mutations are located was made using mismatch PCR assay, ASO hybridization assay, restriction fragment analysis, allele specific PCR assay and direct sequentiation techniques. Two BRCA1 mutations (185delAG and C61G) and one variant of unknown significance (E1250K) were found in four of these families. Also, a new mutation (4185delCAAG) and one previously described polymorphism (E1038G) were found in two other families. The 185delAG was found in a 3.17 % of the families and the others were present only in one of the families of this cohort. Therefore these mutations are not prominent in the Chilean population. The variant of unknown significance and the polymorphism detected could represent a founder effect of Spanish origin