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BACKGROUND The aim of this study was to determine the mediating effect of spontaneous preterm birth (PTB) main predictors that would allow to suggest etiological pathways. METHODS We carried out a case-control study, including sociodemographic characteristics, habits, health care, and obstetric data of multiparous women who gave birth at a maternity hospital from Tucuman, Argentina, between 2005 and 2010: 998 women without previous PTB who delivered at term and 562 who delivered preterm. We selected factors with the greatest predictive power using a penalized logistic regression model. A data-driven Bayesian network including the selected factors was created where we identified pathways and performed mediation analyses. RESULTS We identified three PTB pathways whose natural indirect effect was greater than zero with a 95% confidence interval: maternal age less than 20 years mediated by few prenatal visits, vaginal bleeding in the first trimester mediated by vaginal bleeding in the second trimester, and urinary tract infection mediated by vaginal bleeding in the second trimester. The effect mediated in these pathways showed greater sensitivity to confounders affecting the variables mediator-outcome and exposure-mediator in the same direction. CONCLUSION The identified pathways suggest PTB etiological lines related to social disparities and exposure to genitourinary tract infections. IMPACT Few prenatal visits (

Background Preterm birth (PTB) is the leading cause of perinatal morbimortality worldwide. Genetic and environmental factors could raise PTB risk. The aim of this study was to analyze the contribution of the statistical interaction between genes and vaginal-urinary tract infections (VI-UTI) to the risk of PTB by clinical subtype. Methods Twenty-four SNPs were genotyped in 18 candidate genes from 352 fetal triads and 106 maternal triads. Statistical interactions were evaluated with conditional logistic regression models based on genotypic transmission/disequilibrium test. Results In PTB-idiopathic subtype mothers exposed to UTI, fetal SNPs rs11686474 (FSHR), rs4458044 (CRHR1, allele G), rs883319 (KCNN3), and maternal SNP rs1882435 (COL4A3) showed a nominal significant increment in prematurity risk. In preterm premature rupture of membranes (PPROM), fetal SNP rs2277698 (TIMP2) showed a nominal significant risk increment. In mothers exposed to VI, fetal SNP rs5742612 (IGF1) in PTB-PPROM and maternal SNP rs4458044 (CRHR1, allele C) in spontaneous PTB showed nominal significant increment in prematurity risk. Conclusions Certain maternal and fetal genes linked to infectious/inflammatory and hormonal regulation processes increase prematurity risk according to clinical subtype when mothers are exposed to UTI or VI. These findings may help in the understanding of PTB etiology and PTB prevention. Impact Preterm birth is a major cause of perinatal morbimortality worldwide and its etiology remains unknown.This work provides evidence on the statistical interaction of six genes with gestational vaginal or urinary infections leading to the occurrence of preterm births. Statistical interactions vary according to infection type, genotype (maternal and fetal), and clinical subtype of prematurity.Certain maternal and fetal genetic variants of genes linked to infectious/inflammatory and hormonal regulation processes would increase the risk of prematurity according to clinical subtype and infection type.Our findings may help in the study of etiology of preterm birth and its prevention.

OBJECTIVE To describe lethality of birth defects (BDs) in newborns categorized by gestational age and birth weight and to identify BDs associated with prematurity. STUDY DESIGN Live born infants (n = 16,452) with isolated BDs classified by severity, and 42,511 healthy controls were assigned to categories: adequate growth, preterm, or small for gestational age (SGA). Proportion of cases and BDs' lethality rates were obtained by category and compared with controls. RESULTS Overall fewer malformed than non-malformed infants were of adequate growth, while the opposite occurred in the preterm and SGA categories where gastroschisis and esophageal atresia were among the most outstanding defects. For most severe BDs, the early neonatal death rate was higher than control values in all categories; for mild defects, except cleft lip in the preterm category, they did not differ. Diaphragmatic hernia showed the highest lethality values, while those of spina bifida were among the lowest. Talipes, hypospadias, and septal heart defects were mild defects significantly associated with prematurity. CONCLUSION Although reasons, such as induced preterm delivery of fetuses with certain anomalies, could partially account for their high prematurity rates, susceptibility to preterm birth might exist through underlying mechanisms related with the defects. The identification of BDs associated with prematurity should serve to improve measures that prevent preterm birth especially of fetuses at risk. KEY POINTS · Some BDs predispose to prematurity.. · Prematurity is an additional risk factor for mortality in infants with mild defects.. · Lethality values should be adjusted by gestational age and birth weight..

We are at the dawn of the efforts to describe and understand the origins of genetic diversity in Argentina from high-throughput data. This knowledge is a primary step in the intent of deciphering the specific genetic bases of diseases and drug response in the country. Similarly to other populations across the Americas, genetic ancestry in Argentinean populations traces back into African, European and Native American ancestors, reflecting a complex demographic history with multiple migration and admixture events in pre- and post-colonial times. However, little is known about the sub-continental origins of these three main ancestries. We present new high-throughput genotyping data for 87 admixed individuals across Argentina. This data was combined to previously published data for admixed individuals in the region and then compared to different reference panels specifically built to run population structure analyses at a sub-continental level. Concerning the European and African ancestries, we confirmed previous results about their main origins, and we provide new insights into the presence of other origins that reflect historical records. As for the Native American ancestry, leveraging genotype data for archeological samples in the region in order to gain temporal depth in our analyses, we could identify four Native American components segregating in modern Argentinean populations . Three of them are also found in modern South American populations and are specifically represented in Central Chile/Patagonia, Lowlands and Central Andes geographic areas. The fourth one may be specific to the Central Western region of Argentina. Identifying such component has not been straightforward since it is not well represented in any genomic data from the literature. Altogether, we provide useful insights into the multiple population groups from different continents that have contributed to present-days genetic diversity in Argentina. We encourage the generation of massive genotype data locally to further describe the genetic structure in Argentina., Facultad de Ciencias Naturales y Museo, Instituto Multidisciplinario de Biología Celular

Birth defects are prenatal morphological or functional anomalies. Associations among them are studied to identify their etiopathogenesis. The graph theory methods allow analyzing relationships among a complete set of anomalies. A graph consists of nodes which represent the entities (birth defects in the present work), and edges that join nodes indicating the relationships among them. The aim of the present study was to validate the graph theory methods to study birth defect associations. All birth defects monitoring records from the Estudio Colaborativo Latino Americano de Malformaciones Congénitas gathered between 1967 and 2017 were used. From around 5 million live and stillborn infants, 170,430 had one or more birth defects. Volume-adjusted Chi-Square was used to determine the association strength between two birth defects and to weight the graph edges. The complete birth defect graph showed a Log-Normal degree distribution and its characteristics differed from random, scale-free and small-world graphs. The graph comprised 118 nodes and 550 edges. Birth defects with the highest centrality values were nonspecific codes such as Other upper limb anomalies. After partition, the graph yielded 12 groups; most of them were recognizable and included conditions such as VATER and OEIS associations, and Patau syndrome. Our findings validate the graph theory methods to study birth defect associations. This method may contribute to identify underlying etiopathogeneses as well as to improve coding systems. Fil: Elias, Dario Ezequiel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Campaña, Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina Fil: Poletta, Fernando Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Heisecke Peralta, Silvina Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Gili, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Ratowiecki, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Gimenez, Lucas Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Pawluk, Mariela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Santos, María Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Cosentino, Viviana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Uranga, Rocio. Gobierno de la Provincia de Buenos Aires. Hospital Interzonal Especializado de Agudos y Cronicos San Juan de Dios.; Argentina. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; Argentina Fil: Rittler, Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Hospital Materno Infantil Ramon Sarda ; Gobierno de la Ciudad Autonoma de Buenos Aires; Argentina Fil: López Camelo, Jorge Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina

Colony formation is related to dispersal, philopatry, conspecific attraction, available suitable habitat, proximity and availability of food resources, and reproductive success. In this study we analyzed if female South American sea lions, (SASL, Otaria flavescens), exhibit natal fidelity at a small geographic scale (between colonies of the same breeding area) in a context of a recovering population with population expansion and recolonization. We examined the mitochondrial genetic diversity and investigated spatial genetic structure, considering new and traditional colonies. We recovered 36 haplotypes (23 novel), with the contemporary presence of common and private haplotypes in each colony. AMOVA analysis indicated no population genetic structure, however Fst, SAMOVA and AIS analyses suggested some level of genetic structure between northern and southern colonies. Therefore female SASL display different strategies when they choose where to breed: some are residents of -or return to- one particular colony whereas others disperse within the study area. In conclusion the recolonization of SASL may be the effect of weak female philopatry attenuated and/or interacting with other processes like site fidelity to near-by feeding grounds, breeding success, terrestrial habitat selection for breed and dispersal. Fil: Grandi, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Loizaga de Castro, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Teran, Ester Mercedes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Santos, María Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Bailliet, Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

The aim was to explain differences in the rates of adverse perinatal events in teenage mothers with low and high schooling. The sample was collected from the Latin American Colaborative Study of Congenital Malformations (ECLAMC) database. From a total of 2,443,747 births in 93 hospitals, 66,755 live newborns without congenital malformations were recruited from 2000 to 2017. Teenage mothers were classified according to low, medium, and high schooling. A multivariate model was used that included reproductive history, access to health services, demographic and socioeconomic variables, and ethnic group. The Fairlie decomposition model was applied to quantify the contribution of explanatory variables to the adverse perinatal event rates. Of the 66,755 newborns analyzed, 21.1% (n = 14,078) were born to teenage mothers. Distribution of maternal schooling was 24.2%, 59.8%, and 16% for low, medium, and high schooling, respectively. The highest rates of adverse perinatal events were seen in teenage mothers with low schooling. The variable "access to health services" explained 35%, 37%, and 23% of the disparities in low birthweight, prematurity, and intrauterine growth restriction, respectively, among teenage mother with low and high schooling. Low number of prenatal visits was the only risk factor for the two levels of schooling and the variable that best explained the differences between the rates of adverse perinatal events. From the public health perspective, prenatal care represents a low-cost intervention with the possibility of increased implementation through adequate information for the population and systematic measures in primary care.El objetivo fue explicar las diferencias en la frecuencia de eventos perinatales adversos entre madres adolescentes con baja y alta escolaridad. La muestra poblacional se recogió en la base de datos del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC). Entre 2.443.747 nacimientos ocurridos en 93 hospitales, se reclutaron 66.755 recién nacidos vivos, sin defectos congénitos, durante el período 2000-2017. Las madres adolescentes se clasificaron según su escolaridad en: baja, media y alta. Se utilizó un modelo multivariado, que incluyó efectos reproductivos, acceso a servicios de salud, variables demográficas-socioeconómicas, así como de grupo étnico. El modelo de descomposición de Fairlie se aplicó para cuantificar la contribución de variables explicativas en las frecuencias de eventos perinatales adversos. De los 66.755 recién nacidos investigados, el 21,1% (n = 14.078) fue primigrávida de madres adolescentes. La distribución por escolaridad materna fue de 24,2%, 59,8% y 16% para baja, media y alta escolaridad, respectivamente. Las mayores frecuencias de eventos perinatales adversos se observaron en madres adolescentes con baja escolaridad. La variable “acceso a servicios de salud” explicó un 35%, 37% y 23% de las disparidades en el bajo peso al nacimiento, prematuridad y retardo de crecimiento intrauterino, respectivamente, entre madres adolescentes con baja y alta escolaridad. El bajo número de consultas prenatales fue el único factor de riesgo para los dos niveles de escolaridad y la variable que mejor explica las diferencias entre las frecuencias de eventos perinatales adversos. Desde el punto de vista de la salud pública, ellos representan una intervención de bajo coste, con posibilidad de que se incrementen mediante información adecuada para la población y medidas sistemáticas en los niveles de atención primaria.O objetivo foi explicar as diferenças na frequência de eventos perinatais adversos entre mães adolescentes com baixa e alta escolaridade. A amostra populacional foi coletada na base de dados do Estudo Colaborativo Latino-Americano de Malformações Congênitas (ECLAMC). Entre 2.443.747 nascimentos ocorridos em 93 hospitais, 66.755 recém-nascidos vivos sem defeitos congênitos foram recrutados no período 2000-2017. As mães adolescentes foram classificadas segundo sua escolaridade em: baixa, média e alta. Foi utilizado um modelo multivariado que incluiu efeitos reprodutivos, acesso a serviços de saúde, variáveis demográficas-socioeconômicas e de grupo étnico. O modelo de decomposição de Fairlie foi aplicado para quantificar a contribuição de variáveis explicativas nas frequências de eventos perinatais adversos. Dos 66.755 recém-nascidos pesquisados, o 21,1% (n = 14.078) foi a mãe adolescente. A distribuição por escolaridade materna foi de 24,2%, 59,8% e 16% para baixa escolaridade, média escolaridade e alta escolaridade, respectivamente. As maiores frequências de eventos perinatais adversos foram observadas em mães adolescentes com baixa escolaridade. A variável “acesso a serviços de saúde”; explicou 35%, 37% e 23% das disparidades no baixo peso ao nascer, prematuridade e retardo de crescimento intrauterino, respectivamente, entre mães adolescentes com baixa e alta escolaridades. O baixo número de consultas pré-natais foi o único fator de risco para os dois níveis de escolaridade e a variável que melhor explica as diferenças entre as frequências de eventos perinatais adversos. Do ponto de vista da saúde pública, eles representam uma intervenção de baixo custo, com possibilidade de ser incrementadas por meio de informações adequadas à população e medidas sistemáticas nos níveis de atenção primária.

El Gran Chaco es uno de los biomas de las Tierras Bajas sudamericanas más recientemente poblados por los seres humanos, ha mantenido su diversidad etnolingüística y muestra evidencias de la existencia de contactos interétnicos. El objetivo de este trabajo es reconocer estructuración genética en la fracción nativa de los linajes paternos en las poblaciones chaqueñas, para lo cual se analizaron 116 individuos de poblaciones wichi, toba, chorote y mocoví de Argentina y lengua y ayoreo de Paraguay. Se identificaron los haplogrupos paternos a través de AFLP y posteriormente se determinaron los haplotipos basados en 17 microsatélites del cromosoma Y en los individuos poseedores de linajes nativos. Se agregaron 166 individuos del NOA para comparaciones regionales. Se estimaron frecuencias haplotípicas e índices de fijación. Se construyeron redes medianas y se evaluó la correlación entre las distancias geográficas y genéticas. Se realizaron Análisis de Coordenadas Principales, y se calcularon las posibles barreras genéticas (áreas geográficas donde la diferenciación genética entre poblaciones adyacentes es mayor). Se obtuvieron 167 haplotipos únicos y 43 haplotipos compartidos para las poblaciones de Gran Chaco y NOA. Las distancias FST y el análisis de autocorrelación espacial muestran estructura geográfica de aislamiento por distancia y 3 barreras que separan a tobas de Salta, lengua y ayoreo de Paraguay y mocovíes de Chaco, esperable ya que estas dos últimas son poblaciones que están geográficamente más distantes. Al agregar las muestras del NOA las barreras antes encontradas se mantienen, pero no se evidencian barreras entre las poblaciones de NOA y Gran Chaco, sugiriendo conexiones entre ambas regiones., Gran Chaco is one of the most recently peopled areas from the South American Lowlands; it has kept its ethnolinguistic diversity and shows evidence of interethnic contacts. The goal of this paper is to describe the structure of native male lineages in Gran Chaco populations, for which we analyzed 116 individuals from wichi, toba, chorote, mocoví populations in Argentina and lengua and ayoreo populations from Paraguay. We identified paternal haplogroups by AFLP and haplotypes based on 17 microsatellites. We added to the analyses 166 individuals from the Argentinian Northwest (NOA) for regional comparisons. We estimated haplotypic frequencies and fixation indexes and assessed the correlation between geographic and genetic distances. We performed Principal Coordinates Analysis and calculated possible genetic barriers. We found 167 unique haplotypes, 43of which were shared between the Gran Chaco and NOA populations. FST distances and Autocorrelation Analysis show a geographic pattern of isolation by distance and 3 barriers that segregate the toba from Salta, lengua and ayoreo from Paraguay and the mocovi from Chaco, which is expected since these last two populations are geographically more distant. These barriers persist when the Argentinian Northwest samples are added, but there is no evidence of barriers between the Gran Chaco and Northwest populations, suggesting connections between these two regions., O Grande Chaco é um dos biomas das Terras Baixas sul-americanas mais recentemente povoado pelos seres humanos, tem mantido sua diversidade etnolinguística e apresenta evidências da existência de contatos interétnicos. O objetivo deste trabalho é reconhecer estruturação genética na fração nativa das linhagens paternas nas populações do Chaco, para o qual foram analisados 116 indivíduos das populações wichi, toba, chorote e mocoví da Argentina, e lengua e ayoreo do Paraguai. Foram identificados os haplogrupos paternos por meio de AFLP e, posteriormente, foram determinados os haplótipos baseados em 17 microssatélites do cromossomo Y nos indivíduos possuidores de linhagens nativas. Foram adicionados 166 indivíduos do NOA para comparações regionais. As frequências dos haplótipos e os índices de fixação foram estimados. Redes medianas foram construídas e a correlação entre as distâncias geográficas e genéticas foi avaliada. Foram realizadas Análises de Coordenadas Principais, e calculadas as possíveis barreiras genéticas (áreas geográficas onde a diferenciação genética entre populações adjacentes é maior). Foram obtidos 167 haplótipos únicos e 43 haplótipos compartilhados para as populações do Grande Chaco e NOA. As distâncias FST e a análise de autocorrelação espacial mostram estrutura geográfica de isolamento por distância e 3 barreiras que separam os tobas de Salta, lengua e ayoreo do Paraguai e os mocovís do Chaco, o que é esperado visto que estas duas últimas são populações que estão geograficamente mais distantes. Quando as amostras do NOA foram adicionadas, as barreiras encontradas anteriormente foram mantidas, mas nenhuma barreira foi evidenciada entre as populações do NOA e do Grande Chaco, sugerindo conexões entre as duas regiões., Dossier: Contribuciones antropológicas a la comprensión del pasado en el Gran Chaco sudamericano., Facultad de Ciencias Naturales y Museo

El objetivo fue explicar las diferencias en la frecuencia de eventos perinatales adversos entre madres adolescentes con baja y alta escolaridad. La muestra poblacional se recogió en la base de datos del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas (ECLAMC). Entre 2.443.747 nacimientos ocurridos en 93 hospitales, se reclutaron 66.755 recién nacidos vivos, sin defectos congénitos, durante el período 2000-2017. Las madres adolescentes se clasificaron según su escolaridad en: baja, media y alta. Se utilizó un modelo multivariado, que incluyó efectos reproductivos, acceso a servicios de salud, variables demográficas-socioeconómicas, así como de grupo étnico. El modelo de descomposición de Fairlie se aplicó para cuantificar la contribución de variables explicativas en las frecuencias de eventos perinatales adversos. De los 66.755 recién nacidos investigados, el 21,1% (n = 14.078) fue primigrávida de madres adolescentes. La distribución por escolaridad materna fue de 24,2%, 59,8% y 16% para baja, media y alta escolaridad, respectivamente. Las mayores frecuencias de eventos perinatales adversos se observaron en madres adolescentes con baja escolaridad. La variable “acceso a servicios de salud” explicó un 35%, 37% y 23% de las disparidades en el bajo peso al nacimiento, prematuridad y retardo de crecimiento intrauterino, respectivamente, entre madres adolescentes con baja y alta escolaridad. El bajo número de consultas prenatales fue el único factor de riesgo para los dos niveles de escolaridad y la variable que mejor explica las diferencias entre las frecuencias de eventos perinatales adversos. Desde el punto de vista de la salud pública, ellos representan una intervención de bajo coste, con posibilidad de que se incrementen mediante información adecuada para la población y medidas sistemáticas en los niveles de atención primaria. The aim was to explain differences in the rates of adverse perinatal events in teenage mothers with low and high schooling. The sample was collected from the Latin American Colaborative Study of Congenital Malformations (ECLAMC) database. From a total of 2,443,747 births in 93 hospitals, 66,755 live newborns without congenital malformations were recruited from 2000 to 2017. Teenage mothers were classified according to low, medium, and high schooling. A multivariate model was used that included reproductive history, access to health services, demographic and socioeconomic variables, and ethnic group. The Fairlie decomposition model was applied to quantify the contribution of explanatory variables to the adverse perinatal event rates. Of the 66,755 newborns analyzed, 21.1% (n = 14,078) were born to teenage mothers. Distribution of maternal schooling was 24.2%, 59.8%, and 16% for low, medium, and high schooling, respectively. The highest rates of adverse perinatal events were seen in teenage mothers with low schooling. The variable “access to health services” explained 35%, 37%, and 23% of the disparities in low birthweight, prematurity, and intrauterine growth restriction, respectively, among teenage mother with low and high schooling. Low number of prenatal visits was the only risk factor for the two levels of schooling and the variable that best explained the differences between the rates of adverse perinatal events. From the public health perspective, prenatal care represents a low-cost intervention with the possibility of increased implementation through adequate information for the population and systematic measures in primary care. O objetivo foi explicar as diferenças na frequência de eventos perinatais adversos entre mães adolescentes com baixa e alta escolaridade. A amostra populacional foi coletada na base de dados do Estudo Colaborativo Latino-Americano de Malformações Congênitas (ECLAMC). Entre 2.443.747 nascimentos ocorridos em 93 hospitais, 66.755 recém-nascidos vivos sem defeitos congênitos foram recrutados no período 2000-2017. As mães adolescentes foram classificadas segundo sua escolaridade em: baixa, média e alta. Foi utilizado um modelo multivariado que incluiu efeitos reprodutivos, acesso a serviços de saúde, variáveis demográficas-socioeconômicas e de grupo étnico. O modelo de decomposição de Fairlie foi aplicado para quantificar a contribuição de variáveis explicativas nas frequências de eventos perinatais adversos. Dos 66.755 recém-nascidos pesquisados, o 21,1% (n = 14.078) foi a mãe adolescente. A distribuição por escolaridade materna foi de 24,2%, 59,8% e 16% para baixa escolaridade, média escolaridade e alta escolaridade, respectivamente. As maiores frequências de eventos perinatais adversos foram observadas em mães adolescentes com baixa escolaridade. A variável “acesso a serviços de saúde”; explicou 35%, 37% e 23% das disparidades no baixo peso ao nascer, prematuridade e retardo de crescimento intrauterino, respectivamente, entre mães adolescentes com baixa e alta escolaridades. O baixo número de consultas pré-natais foi o único fator de risco para os dois níveis de escolaridade e a variável que melhor explica as diferenças entre as frequências de eventos perinatais adversos. Do ponto de vista da saúde pública, eles representam uma intervenção de baixo custo, com possibilidade de ser incrementadas por meio de informações adequadas à população e medidas sistemáticas nos níveis de atenção primária. Fil: Ratowiecki, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Santos, María Rita. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Poletta, Fernando Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Heisecke Peralta, Silvina Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Elias, Dario Ezequiel. No especifíca; Fil: Gili, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Gimenez, Lucas. No especifíca; Fil: Pawluk, Mariela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Uranga, Rocio. No especifíca; Fil: Cosentino, Viviana Raquel. No especifíca; Fil: Campaña, Hebe. No especifíca; Fil: Rittler, Mónica. No especifíca; Fil: López Camelo, Jorge S.. No especifíca

Non-syndromic cleft lip with or without cleft palate (NSCLP) is a congenital malformation that shows the characteristics of a multifactorial pathology. In order to describe the genetic predisposition to this disorder, NAT genes were analyzed with special interest since they codify for N-acetyltransferases, the enzymes responsible for the biotransformation of arylamines, hydrazine drugs and a great number of toxins and carcinogens present in diet, cigarette smoke and the environment. The allelic transmission of NAT2 that determines the slow acetylator phenotype in 174 trios (case-mother/father) from ECLAMC (Latin American Collaborative Study of Congenital Malformations) maternities in Argentina was evaluated. The *4, *5B, *6, and *7 variants by PCR-RFLP were analyzed. A higher risk for the 5B*5B* genotypes (OR=2. 24; p=0.050) was found, at the expense of the cases from Patagonia, without the influence of the maternal genotype., El labio leporino con o sin paladar hendido (NSCLP) es una malformación congénita que presenta las características de una patología multifactorial. Se consideran de especial interés los genes NAT que codifican para las Nacetiltransferasas, enzimas responsables de la biotransformación de arilaminas, fármacos de hidrazina, y de un gran número de toxinas y carcinógenos presentes en la dieta, el humo de cigarro y el medio ambiente. Lo expuesto anteriormente ha despertado la sospecha de un posible rol de NAT2 en la manifestación de LL/PH en el recién nacido expuesto. En este trabajo se ha evaluado la transmisión alélica de variantes que determinan el fenotipo acetilador lento en 174 tríos (caso, madre y/o padre) reclutados por el ECLAMC (Estudio Colaborativo Latinoamericano de Malformaciones Congénitas) en maternidades de Argentina. Se analizaron las variantes *4, *5B, *6 y *7 mediante PCR-RFLP. Se halló un riesgo mayor en los casos con genotipos 5B*5B* (OR=2,24; p=0,050), a expensas de los casos de Patagonia, sin influencia del genotipo materno., Asociación de Antropología Biológica de la República Argentina

BACKGROUND:Despite the numerous reports on the limb body wall complex (LBWC), this association has never been adequately defined. Amniotic bands (AB) are frequently present but their role remains unclear. Since most reports were based on clinical and often subjective diagnoses, the aim of this work was to define LBWC and the role of AB, minimizing subjectivity.METHODS:Data were obtained from the ECLAMC maternity hospitals network database. A total of 450 live and stillborn infants, born during 1967-2013, with AB or the LBWC were selected. A hierarchical cluster analysis was used to classify cases into homogeneous groups (sharing similar associated defects); robustness of the classification was confirmed with a discriminant analysis. The frequency of associated defects was compared among groups; those whose frequency differed significantly were included in a logistic regression to establish their association within each group.RESULTS:The cluster analysis identified two groups: a body wall defect (BWD) predominating in one, AB in the other. These groups were further divided into: BWD (cases with only BWD), AB (with only AB), BWD + AB, and NONE (with neither). Association with caudal defects and lower limb amelia was observed for BWD, with cephalic defects and upper limb amputations for BWD + AB.CONCLUSIONS:The results, obtained with the least possible subjectivity, indicated that BWD and BWD + AB are different conditions. Since BWD specifically associates with amelia, we propose that this defect and not any limb deficiency should be considered as inclusion criterium and that it should be included in the BWD acronym as LBWC. Fil: Rittler, Monica. Universidad de Buenos Aires; Argentina Fil: Campaña, Hebe. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Comisión de Investigaciones Científicas, Buenos Aires; Argentina Fil: Poletta, Fernando Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Instituto Nacional de Genética Médica Poblacional; Brasil Fil: Santos, María Rita. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentina Fil: Gili, Juan Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Pawluk, Mariela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Cosentino, Viviana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: Gimenez, Lucas Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina Fil: López Camelo, Jorge Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET; Argentina. Instituto Nacional de Genética Médica Poblacional; Brasil

We analyzed 391 samples from 12 Argentinian populations from the Center-West, East and North-West regions with the Illumina Human Exome Beadchip v1.0 (HumanExome-12v1- A). We did Principal Components analysis to infer patterns of populational divergence and migrations. We identified proportions and patterns of European, African and Native American ancestry and found a correlation between distance to Buenos Aires and proportion of Native American ancestry, where the highest proportion corresponds to the Northernmost populations, which is also the furthest from the Argentinian capital. Most of the European sources are from a South European origin, matching historical records, and we see two different Native American components, one that spreads all over Argentina and another specifically Andean. The highest percentages of African ancestry were in the Center West of Argentina, where the old trade routes took the slaves from Buenos Aires to Chile and Peru. Subcontinentaly, sources of this African component are represented by both West Africa and groups influenced by the Bantu expansion, the second slightly higher than the first, unlike North America and the Caribbean, where the main source is West Africa. This is reasonable, considering that a large proportion of the ships arriving at the Southern Hemisphere came from Mozambique, Loango and Angola., Instituto Multidisciplinario de Biología Celular

Background: NAT genes are considered candidate genes for the genetic predisposition to non-syndromic Cleft lip with or without cleft palate (NSCLP), since they codify for N-acetyltransferases, enzymes responsible for the biotransformation of arylamines, hydrazine drugs, and a great number of toxins and carcinogens present in diet, cigarette smoke, and environment. Aim: To determine the association between alleles determining slow acetylator phenotype and the risk of NSCLP. Material and Methods: We analyzed *5 (481C>T), *6 (590G>A) and *7 (857G>A) alleles which determine the slow acetylator phenotype and *4 (wild type) allele by polymerase chain reaction/restriction fragment length polymorphism in 97 progenitor-case trios of NSCLP in Argentinian Obstetric Wards. We evaluated the transmission disequilibrium (TDT). Results: TDT showed a positive association between allele *5 and NSCLP (odds ratio = 1,6; p = 0,03). Conclusions: The presence of *5 allele is significantly higher in cases with congenital NSCLP., Facultad de Ciencias Naturales y Museo, Instituto Multidisciplinario de Biología Celular

NAT genes are considered candidate genes for the genetic predisposition to non-syndromic Cleft lip with or without cleft palate (NSCLP), since they codify for N-acetyltransferases, enzymes responsible for the biotransformation of arylamines, hydrazine drugs, and a great number of toxins and carcinogens present in diet, cigarette smoke, and environment.To determine the association between alleles determining slow acetylator phenotype and the risk of NSCLP.We analyzed *5 (481CT), *6 (590GA) and *7 (857GA) alleles which determine the slow acetylator phenotype and *4 (wild type) allele by polymerase chain reaction/restriction fragment length polymorphism in 97 progenitor-case trios of NSCLP in Argentinian Obstetric Wards. We evaluated the transmission disequilibrium (TDT).TDT showed a positive association between allele *5 and NSCLP (odds ratio = 1,6; p = 0,03).The presence of *5 allele is significantly higher in cases with congenital NSCLP.

La fisura labiopalatina no sindrómica (LL/PH) constituye una malformación congénita que presenta las características de una patología multifactorial; varios genes candidatos se han estudiado con el fin de describir la predisposición genética de esta malformación. Se consideró de especial interés a los genes NATs que codifican para las N-acetiltransferasas, enzimas responsables de la biotransformación de arilaminas, fármacos de hidrazina, y de un gran número de toxinas y carcinógenos presentes en la dieta, humo de cigarro y medio ambiente. Lo expuesto anteriormente ha despertado la sospecha de un posible rol de NAT2 en la manifestación de LL/PH en el recién nacido expuesto. En primer lugar, se evaluó el desequilibrio de ligamiento de los alelos del gen NAT2 que determinan fenotipo acetilador lento en 97 tríos completos (caso-padres-madres) y en 174 incompletos (caso-padre/madre) de maternidades del ECLAMC, Argentina. Se analizaron las variantes * 4, * 5, * 6 y * 7 por PCR-RFLP. A partir del método TDT se evidenció asociación positiva entre el alelo * 5 y LL/PH (OR = 1,61; p = 0,031). Con el modelo de regresión lineal que mide los efectos maternos y del caso, se observó un riesgo mayor para los genotipos 55 de los casos (OR = 2,24; p = 0,050), sin influencia del genotipo materno. Estos hallazgos demuestran que el alelo * 5 es significativamente mayor en los casos con la anomalía congénita LL/PH. En segundo lugar, debido a la heterogeneidad de la contribución genética en las poblaciones argentinas actuales, analizamos la ancestralidad. En los linajes mitocondriales, se observó una frecuencia del 88% de haplogrupos nativos americanos, mientras que para el cromosoma Y, los haplogrupos nativos mostraron una frecuencia de 22%, variando notablemente de un centro asistencial a otro. Estos resultados sugieren una fuerte contribución nativa para la línea materna pero no para la paterna en las poblaciones urbanas actuales, indicando de esta forma concordancia con los registros históricos sobre mestizajes en Centro y Sudamérica, que involucró mayormente a mujeres americanas y hombres extranjeros., Non-syndromic cleft lip (LL/PH) is a congenital malformation that shows the characteristics of a multifactorial pathology; aiming to describe its genetical predisposition, several candidate genes have been studied. NATs genes were considered with special interest since these codify for N-acetiltransferases, the enzymes responsible for the biotransformation of arilamines, hydrazine drugs and a great number of toxins and carcinogens present in the diet, cigarette smoke and environment. For this, there have been suspicions about the possible role of NAT2 in the LL/PH manifestation on the exposed newborn. Firstly, we evaluated the linkage disequilibrium of the alleles of NAT2 that determine the slow acetylator phenotype in trios, 97 full (case-mother-father) and in 174 incomplete (case-mother/father) of ECLAMC maternities in Argentina. We analized the *4, *5, *5 and *7 variants by PCR-RFLP. By TDT we found a positive association between the allele *5 and LL/PH (OR = 1.61, p = 0.031).With the lineal regression model that measures the maternal and case effects, we found a higher risk for the 55 genotypes of the cases (OR = 2.24, p = 0.050), without the influence of the maternal genotype. These findings show that the *5 allele is significantly higher in the cases with the congenital anomaly LL/PH. Secondly, due to the heterogeneity of the genetical contribution in contemporary Argentinean populations, we studied ancestry. In the mitochondrial lineages we found a high frequency of Native American haplogroups (88%), while for the Y-chromosome the Native American haplogroups had a frequency of 22%, varying considerably between centers. These findings suggest a strong Native American contribution in the maternal line but not in the paternal of urban contemporary populations, thus matching the historical records of admixture in Central and South America, where it was mostly between Native American women and foreign men., Facultad de Ciencias Naturales y Museo

Dear Sirs: The letter by Dr. Athey entitled “Comments on the article, “Software for Y-Haplogroup Predictions, a Word of Caution” discusses a paper of our authoring in the present Journal [1]. Though at first glance his opinion may seem reasonable, a careful analysis reveals a series of mistakes committed by Dr. Athey. In the mentioned letter, one of the main concerns of Dr. Athey is the amount of short tandem repeats (STRs) that were analyzed. He comments that seven markers should be avoided, explaining that an increase of that amount augments the probability of assignment, stating that “With the addition of a sufficient number of markers, the prediction probability for the correct haplogroup can be ‘driven’ past 99% in nearly all cases, and this almost always occurs by the point where 20 markers have been used.” Nonetheless, he does not make reference to any sort of validation study, so said 99% must only refer to the probability of assignment his own software provides. What is more, Dr. Athey seems oblivious that our paper examined this software’s predictive values in different cutoff points, up to 95% of probability of assignment, still obtaining inadequate predictive values on said cutoff point. Twelve of our haplotypes proposed from 100% to 99.6% probability of assignment to the R1b haplogroup in the Haplogroup Predictor, while none of those samples belong to the said haplogroup. In the R haplogroup, one haplotype gives 99.8% probability to an erred haplogroup (E1b1b), while 14 give from 100% to 99.4%, assigning these samples to the R1b haplogroup, and were considered as correct predictions. Note that in these cases, the predicted haplogroup follows the nomenclature of the software, and the probability was not pooled by major branches. If the seven markers of the minimal haplotype were not a proper set, Dr. Athey’s software should not provide such high probabilities of assignment in these cases, since it misleads the user. Unfortunately, Dr. Athey’s mention that seven Y-STRs are too few occurs only in his letter; neither of the two papers of his authoring [2, 3] available at the Haplogroup Predictor’s website (http:// www.hprg.com/hapest5/) nor the software instructions (http://www.hprg.com/hapest5/page4.html) explain that the user should employ more than seven markers. Otherwise, we would not have attempted to use it. Moreover, a simple glance at recent literature where the Haplogroup Predictor was employed clearly shows that researchers do not use such high amounts of Y-STRs when they rely on the Haplogroup Predictor; for instance, Salas et al. [4] used the seven Y-STRs we did, plus DYS 385 and Petrejcikova et al. [5] only 12 Y-STRs. His statement “...indeed, the seven-marker dataset apparently resulted from a study carried out over five M. Muzzio :V. Ramallo : J. M. B. Motti :M. R. Santos : J. S. Lopez Camelo :G. Bailliet Laboratorio de Genetica Molecular Poblacional, Instituto Multidisciplinario de Biologia Celular (IMBICE), CICPBA, CCT, La Plata–CONICET, La Plata, Argentina

Durante el año 2005, se realizaron dos viajes de campaña a comunidades Wichí cercanas a las localidades de Ingeniero Juárez y Laguna Yema (provincia de Formosa, Argentina), como parte del proyecto multidisciplinario “De las historias étnicas a la prehistoria en el Gran Chaco”. Partiendo del planteo metodológico de unidad poblacional, se obtuvieron datos genéticos en 93 muestras utilizando marcadores binarios y microsatélites del cromosoma Y, determinando haplogrupos y haplotipos masculinos. El haplogrupo Q1a3a, natural del continente americano, resultó mayoritario en ambas localidades (72,7 % y 81,6 %). Los linajes moleculares se compararon con la diversidad de apellidos registrada y las posibles vinculaciones entre las comunidades Wichís se analizaron por redes “median joining”, encontrando una variabilidad de linajes coherente con la distribución de las parcialidades del “complejo étnico Wichí” propuesto por Braunstein., During the year 2005, as part of the multidisciplinary project “Of the ethnic histories to the prehistory of the Gran Chaco”, two field trips to the wichi communities nearing the locations of Ingeniero Juarez and Laguna Yema (Formosa province, Argentina) were made. From the methodological proposal of a population unit, genetic data in 93 samples, employing binary markers and microsatellites of the Y-chromosome were obtained, determining male haplogroups and haplotypes. The Q1a3a haplogroup, native of the American continent, resulted the most common in both locations (72,7% and 81,6%). The molecular lineages were compared with the registered surname diversity and the possible links between the wichi communities were analyzed through “median joining” networks, finding a lineage variability that is reasonable given the distribution of the partialities of the “wichi ethnic complex” proposed by Braunstein., Instituto Multidisciplinario de Biología Celular

Seccio ´n Antropologia Biologica, Instituto de Ciencias Antropologicas, Facultad de Filosofia y Letras,Universidad de Buenos Aires, Buenos Aires, ArgentinaKEY WORDS Y chromosome; SNP; microsatellites; south AmericaABSTRACT We analyzed 21 paragroup Q* Y chro-mosomes from South American aboriginal and urbanpopulations. Our aims were to evaluate the phyloge-netic status, geographic distribution, and genetic diver-sity in these groups of chromosomes and compare thedegree of genetic variation in relation to Q1a3a haplo-types. All Q* chromosomes from our series and fivesamples from North American Q* presented the deri-vate state for M346, that is present upstream to M3,and determined Q1a3* paragroup. We found a restric-tive geographic distribution and low frequency ofQ1a3* in South America. We assumed that this lowfrequency could be reflecting extreme drift effects.However, several estimates of gene diversity do notsupport the existence of a severe bottleneck. The meanhaplotype diversity expected was similar to that forSouth American Q1a3* and Q1a3a (0.478 and 0.501,respectively). The analysis of previous reports fromother research groups and this study shows the high-est frequencies of Q* for the West Corner and theGrand Chaco regions of South America. At present,there is no information on whether the phylogeneticstatus of Q* paragoup described in previous reports issimilar to that of Q1a3* paragroup though our resultssupport this possibility. Am J Phys Anthropol 140:578–582, 2009.

The development of online software designed for genetic studies has been exponentially growing, providing numerous benefits to the scientific community. However, they should be used with care, since some require adjustments. The efficiency of two programs for haplogroup prediction was tested with 119 samples of known haplotypes and haplogroups from Argentine populations. Quantitative estimates of the predictive quality of both software systems were computed with the uncertainty coefficient; and sensitivity, specificity, positive, and negative likelihood ratios were also calculated to assert the reliability of both programs, showing high probabilities of assigning an incorrect haplogroup.

Interethnic differences in the allele frequencies of CYP2D6, NAT2, GSTM1 and GSTT1 deletions have been documented for Caucasians, Asians, and Africans population. On the other hand, data on Amerindians are scanty and limited to a few populations from southern areas of South America. In this report we analyze the frequencies of 11 allele variants of CYP2D6 and 4 allele variants of NAT2 genes, and the frequency of GSTM1 and GSTT1 homozygous deleted genotypes in a sample of 90 donors representing 8 Native American populations from Argentina and Paraguay, identified as Amerindians on the basis of their geographic location, genealogical data, mitochondrial- and Y-chromosome DNA markers. For CYP2D6, 88.6% of the total allele frequency corresponded to *1, *2, *4 and *10 variants. Average frequencies for NAT2 *4, *5, *6 and *7 alleles were 51.2%, 25%, 6.1%, and 20.1%, respectively. GSTM1 deletion ranged from 20% to 66%, while GSTT1 deletion was present in four populations in less than 50%. We assume that CYP2D6 *2, *4, *10, *14; NAT2 *5, *7 alleles and GSTM1 and GSTT1 *0/*0 genotypes are founder variants brought to America by the first Asian settlers.

Mutation analysis of the low density lipoprotein receptor (LDLR) gene revealed a novel 8-bp duplication after nucleotide 681 in a Costa Rican patient with familial hypercholesterolaemia. The frameshift caused by this mutation results in a premature termination codon in the EGF precursor homology domain of the mature LDLR, whereby a truncated protein of the first 206 residues with an additional 39 abnormal residues would be created. The insertion overlaps with previously described duplications of 18 bp and 21 bp, thus revealing an insertional hotspot in exon 4 of the LDLR gene. We propose that the structural features of this region of the LDLR gene contribute significantly to genetic instability and the subsequent DNA duplication via an endogenous sequence-directed mechanism of mutagenesis.

We report a new case of a large, homoplasmic Control Region deletion in human mitochondrial DNA. A missing 154bp fragment spanning positions 16154–16307 was found in an apparently healthy blood donor from Salta (NW Argentina) whose maternal lineage was attributable to Native American haplogroup D1. The same mutation, to the best of our knowledge, has been independently reported before only twice, in both homoplasmic and heteroplasmic states.

Y-chromosome haplogroups constructed from SNP markers of Y-specific regions have been largely used in population genetic trials. These data might also be applied to forensic studies on human populations showing multiethnic admixture. Haplogroups have evidenced differential ethnic and geographic distribution. The objective of the present report was to analyze 775 male samples for 16 Y-SNP by PCR-RFLP and to describe haplogroup frequencies in three Argentine geographic regions: Central-West (Cuyo), Center, and North-West.

Combined heteroduplex single-strand conformation polymorphism (HEX-SSCP) analysis of the promoter and coding region of the low density lipoprotein receptor (LDLR) gene revealed a novel C to T mutation at nucleotide position 2056 in a Costa Rican patient with heterozygous familial hypercholesterolemia (FH). This nonsense mutation, Q665X, results in a termination codon in the epidermal growth factor (EGF) precursor homology domain of the mature LDLR.

Artículo científico -- Universidad de Costa Rica, Instituto de Investigaciones en Salud. 1994. Debido a las políticas de la revista en la que el artículo fue publicado, este no es posible distribuir la versión del editor/PDF; no obstante, se adjunta el URL de publicación original. A rapid, simple restriction isotyping method is described for the direct screening of a previously characterized Amerindian mitochondrial DNA (mtDNA) marker ;onsisting of a 6-bp "Huetar" deletion. In a sample of 31 maternally non-related Chibchan Amerindian Bribri from Costa Rica, this deletion was present in 74%, arguing for the usefulness of this private polymorphism for Amerindian taxonomic research. Universidad de Costa Rica, Instituto de Investigaciones en Salud UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto de Investigaciones en Salud (INISA)