Effect of the parental origin of the X-chromosome on the clinical features, associated complications, the two-year-response to growth hormone (rhGH) and the biochemical profile in patients with turner syndrome.

Background: It is possible that genes on the X chromosome are expressed differently depending of its parental origin. The objective of this study was to determine the influence of the parental origin of the X-chromosome on phenotypic variability, response to rhGH and on the biochemical profile of TS patients.

Methods: This was a cross-sectional multicenter correlational study carried out over three years in six Latin-American university hospitals.

New genetic associations in thiopurine-related bone marrow toxicity among inflammatory bowel disease patients.

Background: The toxicity related to thiopurine drug therapy for inflammatory bowel disease (IBD) varies widely among patients. Almost 15-30% of patients with IBD develop side effects during treatment, often bone marrow suppression. Several factors have been implicated in determining this toxicity, mainly individual genetic variation related to formation of active thiopurine metabolites.

Development of a panel of genome-wide ancestry informative markers to study admixture throughout the Americas.

Most individuals throughout the Americas are admixed descendants of Native American, European, and African ancestors. Complex historical factors have resulted in varying proportions of ancestral contributions between individuals within and among ethnic groups. We developed a panel of 446 ancestry informative markers (AIMs) optimized to estimate ancestral proportions in individuals and populations throughout Latin America.

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

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.

[C677T polymorphism of the methylentetrahydrofolate reductase gene as risk factor in women with recurrent abortion].

The pathogenesis of recurrent spontaneous abortion is multifactorial, presumably involving the interaction of several genetic and environmental factors. The methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism has been implicated as risk factor for recurrent spontaneous abortion (RA). The main objective of this research was to investigate the association between the C677T polymorphism of the MTHFR gene as a genetic risk factor for idiopathic RA.

[G138A polymorphism of the RNASEL gene and its association with the development of prostate cancer. Preliminary study].

Prostate Cancer (CAP), is a complex disease with a multifactorial origin. It is characterized by heterogenous patterns of growth of neoplasic tissue, varying widely in its progression, age of beginning and therapy response. It is considered as the second most common cause of death by cancer in men and, it has been estimated, that one of five, suffers of CAP through the course of his life.

[Frequency and clinicopathological associations of K-ras mutations in Venezuelan patients with colo-rectal cancer].

Mutations in the K-ras oncogene are common in colo-rectal cancer, which affect the biological behaviour and may influence the susceptibility to therapy in these tumors. The objective of this work was to identify the types of K-ras mutations observed in referred patients with colo-rectal cancer and to relate them to their degree of histological differentiation and clinical stage. Histopathological and clinical data were obtained from medical records.

[Indirect prenatal molecular diagnostic of haemophilia A and B].

Haemophilia A (HA) and B (HB) are the most common inherited bleeding diseases. HA and HB are X-linked recessive disorders caused by mutation in the factor VIII gene which maps to Xq28 and factor IX located at Xq27, respectively; resulting in absence or deficiency of these proteins. Several mutations have been reported as responsible for the disturbance of these genes; therefore, the use of direct molecular techniques to analyze the carrier status of women and their affected fetuses in not easy to perform.

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

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.

Usefulness of 12 Y-STRs for forensic genetics evaluation in two populations from Venezuela.

The distribution of allele frequencies and haplotypes for 12 STRs loci, (DYS19, DYS389I/II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS437, DYS438 and DYS439) on the Y-chromosome from two Venezuelan populations were determined in 173 DNA samples of unrelated males living in Caracas (62) and Maracaibo (111). Some parameters of forensic importance were calculated. AMOVA and genetic distances between these populations were estimated.

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

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.

[Molecular analysis of microdeletions of the Y chromosome in Venezuelan males with idiopathic infertility].

Today infertility is a major health problem affecting about 10-20% of couples. A male factor is assumed to be responsible in about 50% of the infertile couples. The origin of reduced testicular sperm function is unknown in about 60-70% of cases.

Genetic variation of 15 STR autosomal loci in the Maracaibo population from Venezuela.

Allele frequencies for 15 short tandem repeats (STRs) autosomal loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA, included in the AmpFLSTR Identifiler, Applied Biosystems) were studied in the city of Maracaibo, Venezuela and were compared with other published Latin-American populations for the same loci. Population and forensic parameters were estimated.

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

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.