RESUMO
Neural tube defects (NTDs) are a group of congenital anomalies that affect the central nervious system. Spina Bifida (SB) is the most frecuent NTD in live births andi t is usually associated to disease, disability; and mortality. NTDs are considered as a multifactorial disease. Women who use folic acid periconceptionally are at a 50-70% reduced risk for NTD-affected pregnancies. More than 80 candidates genes to SB are been studied, someones related to folic acid metabolic pathway. MTHFR gene is the gene more studied in NTDs. Its allele 677T is asóciate to higher risk to NTD. It is important to study polymorphisms in MTHFR gene in Chile because Chilean population has dfferent ethnic origen from others previous studied populations.
Assuntos
Humanos , Feminino , Gravidez , Recém-Nascido , Disrafismo Espinal/embriologia , Disrafismo Espinal/genética , Chile , Anormalidades Congênitas , Defeitos do Tubo Neural/embriologia , Defeitos do Tubo Neural/genéticaRESUMO
Background: Nonsyndromic cleft lip/palate (NSCLP) is a congenital malformation with the characteristics of a complex genetic trait. Based on experimental evidences as well as on association and linkage studies candidate genes TGFA, RARA and BCL3 have been postulated as being involved in the genetic etiology of this pathology. Aim: To test the possible association due to linkage disequilibrium between microsatellite markers located at less than 1cM from the three candidate genes and nonsyndromic cleft lip/palate using the case-parents trio design. Patients and Methods: The sample consisted of 58 case-parents trios. Two microsatellite markers, flanking each one of the candidate genes were analyzed by means of the polymerase chain reaction (PCR) with fluorescent labeled microsatellite markers. Electrophoresis of the PCR products was performed on a laser-fluorescent automatic DNA sequencer. Nonparametric ETDT was used to analyze the genotype data. Results: Significant linkage disequilibrium was detected between D2S443 (TGFA) and NSCLP. Significance was almost reached between D17S800 (RARA) and NSCLP. Alleles 239bp (D2S443) and 172bp (D17S800) showed significant preferential transmission from heterozygous parents to affected offspring. In the case of BCL3 both markers showed no significant results. Conclusions: The results of the present study do not show clear evidence that TGFA or RARA could be involved in the genetic etiology of NSCLP. Even though the importance of retinoic acid in the development of the embryo is well documented the results obtained for RARA are difficult to analyze. In relation to the possible role of BCL3 in NSCLP, recent information postulates that other genes located in the same chromosome region could be involved in NSCLP.
Assuntos
Humanos , Fenda Labial/genética , Fissura Palatina/genética , Desequilíbrio de Ligação/genética , Repetições de Microssatélites/genética , Alelos , Chile , Marcadores Genéticos , Genótipo , Proteínas Proto-Oncogênicas/genética , Receptores do Ácido Retinoico/genética , Fatores de Transcrição , Fator de Crescimento Transformador alfa/genéticaRESUMO
Background: In the search of the major genes responsible for the genetic etiology of Nonsyndromic Cleft Lip and Palate (NSCLP), an association study between this malformation and four molecular markers, F13A1 and EDN1 (6p), D17S579 (17q) and BCL3 (19q), was done. Aim: To determine, in a Chilean population, the presence of NSCLP susceptibility regions, as proposed for Caucasian populations in the 6p, 17q and 19q chromosomal regions. Material and Methods: A sample of unrelated NSCLP patients, that belonged to Simplex (Sx) and Multiplex (Mx) families, was analyzed. Blood donors were used as a control group (Co). The DNA of the four markers was amplified by means of PCR, their products analyzed by PAGE denaturants and visualized by silver staining. Statistical analysis was performed using c2 log ratio. Results: Allele frequency distribution of D17S579 was significantly different in all patients with NSCLP and their subgroups, when compared to control subjects. Significant differences in EDN1 frecuency were observed between the total groups of NSCLP patients and those pertaining to the Mx subgroup, when compared to controls. Differences in F13A1 distribution were only observed between NSCLP-Mx patients and controls. There was a slight difference in BCL3 distribution, between the total sample of NSCLP patients and controls. Conclusions: Our results support the hypothesis of the existence of cleft susceptibility regions in 6p and 17q. The small significance of BCL3, suggests that ethnicity can influence the interactions between involved genes