J E Bernal

National University of Colombia, Bogotá, Bogota D.C., Colombia

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Publications (42)66.94 Total impact

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    ABSTRACT: Abstract Objectives: To determine the African, European and Native-American paternal contributions in genetic samples from the Department of Bolivar (Colombia) with the aims of establishing (1) possible population substructures, and (2) the proportion of biological African heritage in admixed populations of European, Amerindian, and African descent. Methods: Y-SNPs were typed in samples from six communities, including Palenque (renowned for its African linguistic and cultural heritage). Results: Findings reveal a high diversity of Y-haplogroups. With the exception of Palenque, the sum of European male lineages uniformly exceeded 57%. In Palenque, African lineages accounted for 57.7% of its chromosomes, with European male lineages constituting a mere 38.5%. In Pinillos, a significant proportion (23.8%) of the chromosomes belongs to the Native American haplogroup Q1a3a*-M3. Genetic differentiation analyses reveal significant divergences in most pairwise comparisons among the Bolivar municipalities, and the same holds between Bolivar and other South American populations. Conclusions: Heterogeneous patterns of admixture reveal a genetic substructure within the Department of Bolivar. On the paternal side, five out of the six communities studied exhibit a predominantly European gene pool. The exception is Palenque, where European input (38%) is more significant than we had expected.
    Annals of Human Biology 11/2013; · 1.48 Impact Factor
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    ABSTRACT: Intrauterine growth restriction is a complication of pregnancy with a high probability of perinatal morbidity and mortality. It appears to be caused by abnormal development of placental vasculature. Haemostatic processes are important for the development of the placenta, and an imbalance between procoagulant and anticoagulant factors has been associated with risk of intrauterine growth restriction. Objective. To evaluate coagulation abnormalities in placenta of pregnancies complicated with idiopathic intrauterine growth restriction. Materials and methods. Five placentas from pregnancies with idiopathic intrauterine growth restriction were compared to 19 controls. We performed gross and histological examination of the placenta. Analysis was made of both mRNA expression by real-time PCR and protein by ELISA of tissue factor and thrombomodulin in placental tissue. Results. Results based on histological evaluation were consistent with an increased prothrombotic state in placentas from pregnancies with idiopathic intrauterine growth restriction, and thrombosis of chorionic vessels was the most important finding. The study showed an increased expression of tissue factor protein (p=0.0411) and an increase in the ratio of tissue factor/thrombomodulin mRNA (p=0.0411) and protein (p=0.0215) in placentas from pregnancies with idiopathic intrauterine growth restriction. There were no statistically significant differences neither between cases and controls in the mRNA levels of tissue factor or thrombomodulin nor at the protein level of thrombomodulin. Conclusion. Evidence of alteration of local haemostatic mechanisms at the level of the placenta, including abnormal expression of tissue factor and tissue factor/ thrombomodulin ratio, in pregnancies that occur with idiopathic intrauterine growth restriction is presented.
    Universitas Scientiarum 08/2012; 17(2):2012.
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    ABSTRACT: Objective: to quantify placenta-specific RNA in plasma of women carrying foetuses with intrauterine growth restriction and pregnant women with normal pregnancies. Materials and methods: 8 pregnant women with foetuses with intrauterine growth restriction were studied as well as 18 women with uncomplicated pregnancies in the third pregnancy trimester. Total free RNA was quantified in maternal plasma by spectrophotometry and the gene expression of hPL (Human Placental Lactogen) at the messenger RNA level through technical Real Time-Chain Reaction Polymerase. Results: plasma RNA of fetoplacental origin was successfully detected in 100% of pregnant women. There were no statistically significant differences between the values of total RNA extracted from plasma (p = 0.5975) nor in the messenger RNA expression of hPL gene (p = 0.5785) between cases and controls. Conclusion: messenger RNA of fetoplacental origin can be detected in maternal plasma during pregnancy.
    Colombia Medica 07/2012; 43(3):184-188. · 0.09 Impact Factor
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    ABSTRACT: Ancient DNA was recovered from 17 individuals found in a rock shelter in the district of "La Purnia" (Santander, Colombia). This region is the homeland of pre-Columbian Guane, whom spread over the "Río Suarez" to the "Río de Oro", and were surrounded to the west by the Central Andes, south and east by foothills of Eastern Andes, and north by the "Chicamocha" river canyon. Guanes established in a region that straddles the Andes and the northern Amazon basin, possibly making it an unavoidable conduit for people moving to and from South America. We amplified mtDNA hypervariable region I (HVI) segments from ancient bone remains, and the resulting sequences were compared with both ancient and modern mitochondrial haplogroups from American and non-American populations. Samples showed a distribution of 35% for haplogroup A, 41% for haplogroup B and 24% for haplogroup D. Nine haplotypes were found in 17 samples, indicating an unusually high genetic diversity on a single site ancient population. Among them, three haplotypes have not been previously found in America, two are shared in Asia, and one is a private haplotype. Despite geographical barriers that eventually isolated them, an important influence of gene flow from neighboring pre-Columbian communities, mainly Muiscas, could explain the high genetic polymorphism of this community before the Spanish conquest, and argues against Guanes as being a genetic isolate.
    American Journal of Physical Anthropology 12/2011; 146(4):637-49. · 2.48 Impact Factor
  • Investigación clínica 12/2011; 52(4):334-343. · 0.39 Impact Factor
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    ABSTRACT: Cardiac defects are the most frequent congenital malformations, with an incidence estimated between 4 and 12 per 1000 newborns. Their etiology is multifactorial and might be attributed to genetic predispositions and environmental factors. Since 1990 these types of pathologies have been associated with 22q11 microdeletion. In this study, the frequency of microdeletion 22q11 was determined in 61 patients with non-syndromic congenital heart disease. DNA was extracted from peripheral blood and TUPLE1 and STR D10S2198 genes were amplified by multiplex PCR and visualized in agarose gels. Gene content was quantified by densitometry. Three patients were found with microdeletion 22q11, representing a 4.9% frequency. This microdeletion was associated with two cases of Tetralogy of Fallot and a third case with atrial septal defect (ASD). In conclusion, the frequency for microdeletion 22q11 in the population analyzed was 4.9%. The cases that presented Teratology of Fallot had a frequency for this microdeletion of 7.4% and for ASD of 11.1%.
    Investigación clínica 12/2011; 52(4):334-43. · 0.39 Impact Factor
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    ABSTRACT: High prevalence of somatic mutations in the cardiac transcription factor genes NKX2.5 and GATA4 have been reported in the affected cardiovascular tissue of patients with isolated cardiac septal defects, suggesting a role of somatic mutations in the pathogenesis of these congenital heart defects (CHDs). However, all somatic mutations have been identified in DNA extracted from an archive of formalin-fixed cardiac tissues. In the present study, to address the hypothesis that somatic mutations are important in isolated CHDs, we analyzed the GATA4 and NKX2.5 genes in the fresh-frozen pathologic cardiac tissue specimen and corresponding non-diseased tissue obtained from a series of 62 CHD patients, including 35 patients with cardiac septal defects and 27 with other cardiac anomalies. We identified one variant and two common polymorphisms in the NKX2.5 gene, and six variants and two common polymorphisms in the GATA4 gene. All identified variants were seen in both the fresh-frozen pathologic cardiac tissue and the corresponding non-diseased tissue, which indicates that they all were constitutional variants. The present study has identified NKX2.5 and GATA4 constitutional variants in our CHD cohort, but was unable to replicate the previously published findings of high prevalence of somatically derived sequence mutations in patients with cardiac septal defects using fresh-frozen cardiac tissues rather than formalin-fixed tissues.
    European journal of medical genetics 01/2011; 54(3):306-9. · 1.57 Impact Factor
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    ABSTRACT: The research of the role of gene polymorphisms in the metabolic pathways of homocysteine-methionine and folic acid in congenital malformations is very important because its effect could be modulated. Objetive: The aim of this study was to determine whether the C677T polymorphism in the gene of the enzyme methylenetetrahydrofolate reductase (MTHFR) was associated with the development of isolated congenital heart disease. Methodology: We compared the allele and genotype frequencies of this polymorphism in 34 infants with isolated congenital heart defects and 102 healthy individuals. Genotyping was performed by Polymerase Chain Reaction (PCR) and with the technique Restriction Fragment Length Polymorphism (RFLP). Results: There were no statistically significant differences in allele or genotype frequencies between case and control groups. Although our results show no statistically significant differences between the groups assessed there was a statistical trend for a possible protective effect of TT genotype against the development of congenital heart disease.
    Universitas Médica. 01/2011; 52(3):269-277.
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    ABSTRACT: The discovery of circulating free fetal nucleic acids in maternal plasma has sparked wide interest in their origin, characteristics and possible medical uses. This review provides a comprehensive and concise summary of the results of studies of free fetal DNA and RNA in maternal plasma and discusses future possibilities for their use, mainly aimed at non-invasive prenatal diagnosis, an area where this discovery is expected to have a major impact in the very near future. Promising results have been reported in the assessment of placental function and in the use of these nucleic acids as predictive markers of the severity of pregnancy complications.
    Clínica e Investigación en Ginecología y Obstetricia 01/2010;
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    ABSTRACT: Ancient bone remains constitute an important source of biological information, and their genetic characterization allows the confirmation or rebuttal of human affiliations proposed on the basis of non-molecular approaches. Pre-Columbian history of the Eastern Andes in Colombia has been divided into three main periods: (i) an early colonization by groups of hunter-gatherers, (ii) an intermediate period "Herrera" characterized by primitive agriculture and (iii) a late stage of Chibcha-speaking groups, with agriculture and ceramics ("agroalfarero"). The mitochondrial DNA on ancient bone remains of the Herrera period were analyzed for comparison with modern and other ancient DNAs. Mitochondrial DNA was extracted from 11 Herrera individuals [approximately 2,000 years before present (YBP)] found in the Madrid 2-41 archaeological site near Bogotá, Colombia. A 192 bp segment of the hypervariable segment I was amplified and sequenced, following stringent archaic DNA authenticity criteria. The sequences were compared with those in American and European databases using bioinformatics tools. All individuals had identical sequences and were classified as haplogroup B. This identity may be related to the type of ritual burial performed in the site, probably exclusively for members of a hierarchically important family of the ancient Herrera society. The search for homologous sequences in the American and European mtDNA data bases produced no identical coincidences, although a Brazilian Amazonic individual (approximately 4,000 YBP) was recorded with a matching sequence. Individuals buried in the Madrid 2-41 site were maternally closely related and showed a mtDNA sequence that is apparently absent in contemporary populations.
    Biomédica: revista del Instituto Nacional de Salud 01/2009; 28(4):569-77. · 0.32 Impact Factor
  • J E Bernal, I Briceno
    Case Reports 01/2009; 2009:bcr2007133678.
  • J E Bernal, I Briceño
    Archivos de la Sociedad Espanola de Oftalmologia 12/2008; 83(11):679-80.
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    Biomédica: revista del Instituto Nacional de Salud 12/2008; · 0.32 Impact Factor
  • J E Bernal, I Briceno
    Archives of Disease in Childhood - Fetal and Neonatal Edition 06/2008; 93(3):F245. · 3.45 Impact Factor
  • J. E. Bernal, I. Briceño
    Archivos de la Sociedad Espanola de Oftalmologia 01/2008; 83(11).
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    ABSTRACT: We examined mitochondrial DNA (mtDNA) haplogroup and haplotype diversity in 188 individuals from three Chibchan (Kogi, Arsario, and Ijka) populations and one Arawak (Wayuú) group from northeast Colombia to determine the biological relationship between lower Central American and northern South American Chibchan speakers. mtDNA haplogroups were obtained for all individuals and mtDNA HVS-I sequence data were obtained for 110 samples. Resulting sequence data were compared to 16 other Caribbean, South, and Central American populations using diversity measures, neutrality test statistics, sudden and spatial mismatch models, intermatch distributions, phylogenetic networks, and a multidimensional scaling plot. Our results demonstrate the existence of a shared maternal genetic structure between Central American Chibchan, Mayan populations and northern South American Chibchan-speakers. Additionally, these results suggest an expansion of Chibchan-speakers into South America associated with a shift in subsistence strategies because of changing ecological conditions that occurred in the region between 10,000-14,000 years before present.
    American Journal of Physical Anthropology 06/2007; 133(1):753-70. · 2.48 Impact Factor
  • J E Bernal, I Briceno
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    ABSTRACT: The people of Tumaco-La Tolita culture inhabited the borders of present-day Colombia and Ecuador. Already extinct by the time of the Spaniards arrival, they left a huge collection of pottery artifacts depicting everyday life; among these, disease representations were frequently crafted. In this article, we present the results of the personal examination of the largest collections of Tumaco-La Tolita pottery in Colombia and Ecuador; cases of Down syndrome, achondroplasia, mucopolysaccharidosis I H, mucopolysaccharidosis IV, a tumor of the face and a benign tumor in an old woman were found. We believe these to be among the earliest artistic representations of disease.
    Clinical Genetics 10/2006; 70(3):188-91. · 3.94 Impact Factor
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    ABSTRACT: Homocystinuria is an autosomal recessive disease most commonly caused by mutations in cystathionine beta-synthase (CBS). In this study we present the mutation analysis of 36 Colombian individuals from 10 unrelated kindred, with 11 individuals clinically classified as homocystinuric. Mutation analysis of the CBS gene revealed p.T191M, a prevalent mutation in Spain and Portugal, in the homozygous state in seven of the unrelated patients. Genotype-phenotype assessment of the p.T191M homozygous patients showed a high level of variability, including different severity in one pair of affected siblings. None of the patients responded biochemically to treatment with pharmacological doses of pyridoxine and folic acid as revealed by essentially unchanged homocysteine levels. This study offered a unique opportunity to study 18 heterozygous (p.T191M/wt) relatives of the homocystinuric patients. One atypical finding was that many of them presented with above average total homocysteine levels, putting them at an increased risk for vascular disease. Cryptorchidism was present in three of the cases, one of which presented also with Klinefelter syndrome. In addition to the previously described p.T191M mutation, a new mutation, p.A288T, was identified in a single individual. In this paper we present the first characterization, at a molecular level, of patients with homocystinuria from Colombia.
    Human Mutation 03/2006; 27(3):296. · 5.21 Impact Factor
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    ABSTRACT: Classical homocystinuria is due to cystathionine beta-synthase (CBS) deficiency. More than 130 mutations, which differ in prevalence and severity, have been described at the CBS gene. Mutation p.I278T is very prevalent, has been found in all European countries where it has been looked for with the exception of the Iberian peninsula, and is known to respond to vitamin B6. On the other hand, mutation p.T191M is prevalent in Spain and Portugal and does not respond to B6. We analysed 30 pedigrees from Spain, Portugal, Colombia and Argentina, segregating for homocystinuria. The p.T191M mutation was detected in patients from all four countries and was particularly prevalent in Colombia. The number of p.T191M alleles described in this study, together with those previously published, is 71. The prevalence of p.T191M among CBS mutant alleles in the different countries was: 0.75 in Colombia, 0.52 in Spain, 0.33 in Portugal, 0.25 in Venezuela, 0.20 in Argentina and 0.14 in Brazil. Haplotype analyses suggested a double origin for this mutation. No genotype-phenotype correlation other than the B6-nonresponsiveness could be established for the p.T191M mutation. Additionally, three new mutations, p.M173V, p.I429del and c.69_70+8del10, were found. The p.M173V was associated with a mild, B6-responsive, phenotype.
    Journal of Human Genetics 02/2006; 51(4):305-13. · 2.53 Impact Factor
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    ABSTRACT: We report the frequencies of alleles at the microsatellite locus D12S67 in 2 widely separated ethnic groups of the world: 2 populations from Sulawesi, an island in the Indonesian archipelago, and 5 Native American tribes of Colombia, South America. The allele frequencies in the Minihasans and Torajans of Sulawesi are similar to each other (but the modal class allele is different) and in general agreement with those reported in mainland Asian groups, but different from both Europeans and Chinese Han of Taiwan. The 5 Native American tribes (Arsario, Kogui, Ijka, Wayuu, and Coreguaje) display different allele frequencies from those seen in Sulawesi populations, in other groups from Europe and mainland Asia, and in Chinese Han of Taiwan. Native Americans exhibit a bimodal distribution of alleles, unlike other groups, with significant differences among the tribes. The Arsario and Kogui have no admixture with Europeans or Africans and are the most distinctive, while the Wayuu have the most admixture and show most similarity to other groups. The data suggest that nonadmixed Native Americans may be quite distinctive with respect to this marker. The most common allele varies across the 5 tribes, from 249 base pairs to 261 base pairs. All samples exhibit Hardy-Weinberg genotype proportions; heterozygosities are lowest in the 2 nonadmixed Native American tribes. Examination of all the available data indicates that some east Asian and southeast Asian groups are characterized by a high frequency of smaller sized D12S67 alleles, while other populations have a greater proportion of the larger sized alleles. The cumulative, though still highly restricted, population data on locus D12S67 demonstrate that it may be of considerable value in anthropological genetic studies of ethnic groups. Data are required on Native Americans outside Colombia before this marker can be used in admixture studies of this group.
    Human Biology 09/2000; 72(4):697-705. · 1.52 Impact Factor

Publication Stats

218 Citations
66.94 Total Impact Points


  • 2011
    • National University of Colombia
      • Instituto de Genética - IGUN (Bogotá)
      Bogotá, Bogota D.C., Colombia
  • 1988–2011
    • Pontifical Xavierian University (Bogota)
      • • Institute for Human Genetics
      • • School of Medicine
      Μπογκοτά, Bogota D.C., Colombia
  • 2000
    • La Trobe University
      Melbourne, Victoria, Australia
  • 1996
    • Newcastle University
      Newcastle-on-Tyne, England, United Kingdom
  • 1994
    • Loughborough University
      Loughborough, England, United Kingdom