Associação entre polimorfismos na região VNTR do gene aggrecan e a hérnia de disco lombar

• Autor(a) principal: Casa, Nara Lígia Leão
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/6830
• topic: Deslocamento do disco intervertebral; Degeneração do disco intervertebral; Polimorfismo genético; Proteoglicano; Acan; Dislocation of intervertebral disc; Degeneration of intervertebral disc; Genetic polymorphism; Proteoglycan; Acan; CIENCIAS DA SAUDE::MEDICINA

Introduction: Lumbar disc herniation (LDH) is the most common diagnosis among the degenerative changes in the lumbar spine and it can lead to functional limitations. Although several studies have shown a positive association between polymorphisms in the aggrecan gene and LDH, results are conflicting and vary across populations. Until now, such studies have not been carried out in Brazil. An understanding of this association can help in the prevention and intervention processes in patients with LDH. Objective: Investigate the association between polymorphisms in the aggrecan gene and LDH. Methods: This is a Case-Control study, paired by gender and age. A total of 119 male and female individuals from Goiania (Brazil) participated in the study; 39 individuals in the Case Group (CaG) and 80 in the Control Group (CtG). For each individual, sociodemographic and clinical data were collected as well as blood samples for genetic analysis. DNA was isolated and genotyped at the variable number of tandem repeats (VNTR) region of the aggrecan gene using polymerase chain reaction. Results: Both groups were homogeneous for socio-demographic, anthropometric, and life style variables. The sum of allele sizes at the VNTR region of the aggrecan gene were significantly lower in individuals with LDH, with allele A22 showing significantly higher frequency in this group. Comparison of allele size distribution indicated that shorter alleles (i.e., A13-A25) were more frequent in individuals with LDH, whereas alleles with a higher number of repeats were more frequent among healthy individuals. It should be noted, however, that differences were not significant. The most frequent alleles in both groups were A28, A27 and A29, respectively. Genotype A26/A26 was the most common among individuals in the CaG. Conclusions: An association between short alleles and LDH was observed in this study. This finding is in agreement with other reports in the literature, corroborating the hypothesis that individuals with shorter alleles have an aggrecan gene with fewer repeats. Therefore, a smaller number of chondroitin sulfate chains bind to the aggrecan in the intervertebral disc, leading to a decrease in its physiological function of hydration of the intervertebral disc, and thus to an increase in LDH susceptibility.