RESUMO
OBJECTIVE: To explore the possible association/s of the first reported tumour necrosis factor (TNF-alphaTNF-) alpha promoter gene polymorphisms -308, -238, -376 and -163 (G-->A) with systemic (SoJIA) and oligoarticular subtypes of juvenile idiopathic arthritis (JIA); and to test the association between these polymorphisms and the class I/class II HLA alleles in our population. METHODS: The patient group comprised 29 oligoarticular and 26 systemic Caucasian Spanish children with JIA; 68 healthy volunteers from the same ethnic group and geographical region served as controls. HLA alleles were determined using low-resolution polymerase chain reaction (PCR). TNF-alpha promoter gene polymorphisms were screened using PCR denaturing gradient gel electrophoresis (PCR-DGGE), followed, if positive, by restriction fragment length polymorphism (RFLP) analysis for identification. RESULTS: No statistical association was found between the four polymorphisms studied and JIA. However, the -308 G-->A polymorphism (TNF A2) tended to be more frequent in patients with SoJIA than in the oligoarticular group. TNF A2 was strongly associated with the extended haplotype A1B8DR3 (p = 0.003), and the tandem polymorphism -238/-376 in the presence of B18 and DR3. CONCLUSION: The TNF A2 allele was more frequent in SoJIA than in the oligoarticular group. TNF A2 can help to create a more inflammatory milieu in this JIA subtype, in combination with other polymorphisms involved in regulatory sequences of key molecules in the inflammatory response. The association of the -308 and -238/-376 polymorphisms with specific alleles of the HLA is reconfirmed.
Assuntos
Artrite Juvenil/genética , Polimorfismo Genético , Regiões Promotoras Genéticas , Fator de Necrose Tumoral alfa/genética , Artrite Juvenil/etnologia , Criança , Intervalos de Confiança , Frequência do Gene/genética , Predisposição Genética para Doença , Humanos , Razão de Chances , Espanha/etnologiaRESUMO
We have designed a new PCR-DGGE technique that enables detection of base changes in the TNF-alpha gene promoter. Screening of 130 samples from Spanish children has shown that this technique accurately detects the altered band patterns induced by the presence of the polymorphisms at positions -376, -308, -238 and -163 of the promoter sequence. Although further analysis are needed to fully characterise the alterations detected, we believe that this PCR-DGGE technique is a rapid and sensitive first approach to the genetic characterisation of the TNF-alpha promoter.
Assuntos
Reação em Cadeia da Polimerase/métodos , Regiões Promotoras Genéticas/genética , Fator de Necrose Tumoral alfa/genética , Criança , DNA/análise , DNA/genética , Eletroforese em Gel de Poliacrilamida , Testes Genéticos , Genótipo , Humanos , Polimorfismo Genético , Polimorfismo de Fragmento de Restrição , Sensibilidade e EspecificidadeRESUMO
The molecular events leading to the development of pediatric bone tumors are not clear to date, but abnormal cell cycle progression has been reported in a wide variety of human tumors due to the alteration of several tumor suppressor genes. We have analyzed 55 bone sarcoma samples from pediatric patients to test the possibility that they harbor mutations in the p21WAF1 tumor suppressor gene. Mutation analysis was performed through denaturing gradient gel electrophoresis analysis of exon 2 of the gene and consequent cycle sequencing of the altered fragments. No mutations affecting the coding regions of the p21WAF1 were found. Nevertheless, we found genetic polymorphisms in nine of the samples analyzed. We conclude that p21WAF1 mutations do not play an important role in the development of this kind of pediatric malignancy.
