Publications by authors named "Lennie Pineda"

7 Publications

  • Page 1 of 1

A melting pot of multicontinental mtDNA lineages in admixed Venezuelans.

Am J Phys Anthropol 2012 Jan 25;147(1):78-87. Epub 2011 Nov 25.

Unidade de Xenética, Instituto de Medicina Legal and Departamento de Anatomía Patolóxica y Ciencias Forenses, Universidade de Santiago de Compostela, Galicia, Spain.

The arrival of Europeans in Colonial and post-Colonial times coupled with the forced introduction of sub-Saharan Africans have dramatically changed the genetic background of Venezuela. The main aim of the present study was to evaluate, through the study of mitochondrial DNA (mtDNA) variation, the extent of admixture and the characterization of the most likely continental ancestral sources of present-day urban Venezuelans. We analyzed two admixed populations that have experienced different demographic histories, namely, Caracas (n = 131) and Pueblo Llano (n = 219). The native American component of admixed Venezuelans accounted for 80% (46% haplogroup [hg] A2, 7% hg B2, 21% hg C1, and 6% hg D1) of all mtDNAs; while the sub-Saharan and European contributions made up ∼10% each, indicating that Trans-Atlantic immigrants have only partially erased the native American nature of Venezuelans. A Bayesian-based model allowed the different contributions of European countries to admixed Venezuelans to be disentangled (Spain: ∼38.4%, Portugal: ∼35.5%, Italy: ∼27.0%), in good agreement with the documented history. Seventeen entire mtDNA genomes were sequenced, which allowed five new native American branches to be discovered. B2j and B2k, are supported by two different haplotypes and control region data, and their coalescence ages are 3.9 k.y. (95% C.I. 0-7.8) and 2.6 k.y. (95% C.I. 0.1-5.2), respectively. The other clades were exclusively observed in Pueblo Llano and they show the fingerprint of strong recent genetic drift coupled with severe historical consanguinity episodes that might explain the high prevalence of certain Mendelian and complex multi-factorial diseases in this region.
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http://dx.doi.org/10.1002/ajpa.21629DOI Listing
January 2012

[Intragenic polymorphisms of factor VIII and IX genes and their utility in the indirect diagnosis of carriers of Haemophilias A and B].

Invest Clin 2010 Sep;51(3):391-401

Laboratorio de Genética Molecular, Unidad de Genética, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venzuela.

Haemophilia A and B are considered sex-linked inherited diseases caused by mutations in genes that encode factors VIII and IX, respectively. This results in the deficiency of these proteins plasma levels which are actively involved in the mechanism of blood coagulation. It has been reported that several mutations are responsible for the alteration of these genes, which is why the application of a molecular diagnostic method for the direct identification of female carriers is impractical. An appropriate diagnostic strategy is the indirect analysis of polymorphisms linked to the gene. The aim of this study was to identify female carriers in different families with history of HA and HB that live in Zulia State, Venezuela, characterizing intragenic gene polymorphisms of the clotting factors VIII and IX, which helped to identify and assign haplotypes, to diagnose or to exclude the carrying condition, to 95% of women who were needing the study for HA and to 100% for HB.
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September 2010

[Association of the vitamin D receptor gene BBAAtt haplotype with osteoporosis in post-menopausic women].

Invest Clin 2008 Mar;49(1):29-38

Cátedra de Bioquímica Clínica, Escuela de Bioanálisis, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Osteoporosis (OP) is an important public issue affecting more than 150 millions all over the world, mainly post-menopausic women. Epidemiological studies have shown that the genetic factors could be involved in 80-90% of the bone mineral density variabiblity and therefore, related to the risk of OP manifestations. The vitamin D receptor (VRD) gene has been extensively studied, but its relationship with OP has been controversial. The aim of this investigation was to study the association of Bsm I, Apa I and Taq I VDR gene polymorphism with OP in 147 post-menopausic women; 71 with OP and 76 without the disease (control). The molecular gene analysis was performed using the polymerase chain reaction (PCR). The genotypes BB, AA, and tt were found in 56.33, 50.70 and 25.35% and in 21.05, 28.95 and 10.53% of OP patients and controls respectively. The haplotype BBAAtt was observed in 23.94% of OP patients and 5.26% of the controls. This haplotype was a risk factor for OP, since a odds ratio (OR) of 5.66 was found, while, haplotype BbaaTT was a protection factor (OR: 0.10). These findings support the association of the vitamin D receptor gene BBAAtt haplotype with OP.
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March 2008

[Molecular analysis of the GABRB3 gene in autistic patients: an exploratory study].

Invest Clin 2007 Jun;48(2):225-42

Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Autism is a complex neurodevelopmental disorder characterized by impairment of social interaction, language, communication, and stereotyped, repetitive behavior. Genetic predisposition to Autism has been demonstrated in families and twin studies. There is evidence (linkage and genetic association, biochemical, neuropathological, functional and cytogenetic) that the gamma-amino-butyric acid receptor beta 3 subunit gene (GABRB3) at 15q11-q13 is a susceptibility candidate gene for Autism. The aim of this exploratory study was to identify new variants of this gene. We performed the molecular analysis (SSCP/Sequencing) of 10 exons and its intronic flanking regions of GABRB3, using a candidate gene screening approach in 18 idiopathic autistic patients. We did not find non-synonymous mutations at the encoding regions, but we identified four SNP (Single Nucleotide Polymorphism). The first one, represented a silent mutation p.P25P in exon la and was found in 33.33% of the patients. The second one: IVS3 + 13C > T (5b far from the intron 5' consensus sequence), was found in 44.44% of the patients, while it was also identified in 16.67% of the controls. Simultaneously, 33.33% of the patients had both variants, and although, 16.67% of the controls also had the same combination of variants, 66.66% of the patients with those alleles had a familiar history of Autism. The third and fourth SNP: IVS5 + 40T > G and IVS-70A > G were identified in two different patients. None of the last three SNPs have been reported at the SNP database (dbSNP). The proximity of SNP: IVS3 + 13C > T with the consensus and interaction sequence with U1 nucleoriboprotein, could disturb the normal splicing of mRNA. This is in agreement with the evidence of lower levels of GABA-A receptors in autistic brains; so, it could be a common variant, that by itself could not cause a phenotypic effect, but joined to other variants with the same gene, in different related genes or with epigenetic changes, could explain the autistic phenotype and its heterogeneity.
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June 2007

High incidence of Y-chromosome microdeletions in gonadal tissues from patients with 45,X/46,XY gonadal dysgenesis.

Fertil Steril 2008 Feb 25;89(2):458-60. Epub 2007 May 25.

Unidad de Genética Médica, Maracaibo, Venezuela.

A higher incidence of Y-chromosome microdeletions was found on gonadal DNA than on peripheral blood lymphocyte DNA and on streak gonads than on dysgenetic testis in 11 patients with 45,X/46,XY gonadal dysgenesis. It is probable that an association between Y-chromosome microdeletions and severity of the phenotype in 45,X/46,XY patients exists.
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http://dx.doi.org/10.1016/j.fertnstert.2007.02.058DOI Listing
February 2008

[Frequency of delta F508 mutation in Venezuelan patients with cystic fibrosis].

Invest Clin 2004 Jun;45(2):121-30

Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Cystic Fibrosis (CF) is the most common and severe autosomal recessive disease in Caucasian populations, with an incidence of 1 in 2500 live births. It is characterized by a generalized disturbance in exocrine glands and it is caused by over one thousand mutations at the cystic fibrosis conductance regulator gene (CFTR) mapped at 7q31. AF508 is the most frequent mutation worldwide and it consists in a deletion of the codon that encodes fenilalanine at the 508 protein's position. The aim of this study was to determine the frequency of the delta F508 mutation in Venezuelan patients with CF using the Polymerase Chain Reaction (PCR). We studied thirty patients of twenty eight families who were diagnosed with CF based on their clinical features and sweat chloride level > 60 mEq/l in two determinations. Detection of the mutation was performed from the amplification of a 98 pair of bases (pb) CF gene segment which contains the codon that encodes fenilalanine in the 508 position by PCR. This PCR product is absent in those who have the mutation. The delta F508 allelic frequency was 26.79%, distributed in six homozygous and seven compound heterozygote delta F508/X. The reminder mutations (no delta F508) represent 73.21%. The delta F508 frequency in our sample is less than the reported in European countries. On the other hand, a delta F508 frequency highly heterogeneous has been observed in Latin-American countries. This variation results from mixed populations with a different genetic background influenced by external migration and CF molecular alterations, which exists in the analyzed populations. In this study, the delta F508 mutation comes mainly from grandparents (79.41%) who were born in Mediterranean countries and Colombia, while the no delta F508 mutations come from grandparents who were born in Venezuela (79.27%) and Colombia (17.07%).
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June 2004

[Analysis of Bsm I polymorphism of the vitamin D receptor (VDR) gene in Venezuelan female patients living in the state of Zulia with osteoporosis].

Invest Clin 2003 Dec;44(4):275-82

Laboratorio de Genética Molecular, Unidad de Genética Médica, Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Among genes implied on the osteoporosis genetics, the most studied gene worldwide is the receptor gene of D vitamin (VDR), through the characterization of Bsm I polymorphism. The main objective of this research was to analyze the Bsm I polymorphism of the VDR gene in a sample of 133 postmenopausal women distributed in three groups: 54 with osteoporosis, 24 with osteopenia and 55 normal controls for the disease. 28 of the women with osteoporosis presented the BB genotype, which is related in other countries to bone mineral density decrease, 20 had the Bb genotype, and 6 the bb genotype. Of the control group only 11 women presented the BB genotype, 36 showed the heterozygote genotype and 8 the bb genotype. The frequencies of the B and b alleles in the analyzed population were 0.6 and 0.4 respectively. The BB genotype was found in 52% of the group with osteoporosis, and in 20% of the control group, these findings are statistically significant, which suggest an association between the BB genotype and osteoporosis.
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December 2003