RESUMEN
Obesity and overweight are worldwide public health problems with an evident genetic predisposition that is still poorly understood. In addition, great variability has been described across populations. In this work, we analyzed the association of variants in four genes: PPARG (rs1801282), PPARGC1A (rs8192678), FTO (rs9939609) and MC4R (rs17782313) with overweight and obesity in a large sample of the Brazilian population. The case-control study involved 4084 individuals (1844 with overweight or obesity; and 2240 with normal BMI). Genotyping was performed by quantitative PCR. MC4R rs17782313-C was associated with obesity (OR = 1.27, p = 0.038) and when stratifying by sex associated only in women (OR = 1.36, p = 0.030). FTO rs9939609-A allele was associated with overweight however for women it represented a risk factor (OR = 1.24, p = 0.034) and for men, a protective factor (OR = 0.68, p = 0.033). PPARG was the strongest associated gene, with both overweight and obesity, and this association was also restricted to women (rs1801282-GG OR = 1.46, p = 0.027). The combined effect of the three risk alleles on overweight and obesity had an OR of 1.65 (p = 0.008) and when stratifying by sex again it was significant only in females (OR = 1.95, p = 0.0028). Our findings indicate that the three genes play a significant role in predisposing to overweight and/or obesity in the Brazilian population, reaching together a relatively high impact on these traits. Interestingly our results also suggest a strong sex-specific genetic effect of these variants.
Asunto(s)
Sobrepeso , PPAR gamma , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Índice de Masa Corporal , Estudios de Casos y Controles , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Obesidad/genética , Sobrepeso/genética , PPAR gamma/genética , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma , Polimorfismo de Nucleótido Simple , Receptor de Melanocortina Tipo 4/genéticaRESUMEN
BACKGROUND: The interferon pathways have been commonly implicated in autoimmune disease development but the identity of the genes involved has not yet been fully clarified. Variation in genes involved in interferon pathways is expected to have a role in the etiology of these diseases. METHODS: The potential association of a polymorphism in the IL28RA gene, involved in these pathways, with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and disease-related phenotypes was investigated in 603 Brazilian individuals (354 well-characterized SLE and RA patients, and 249 controls). IL28RA (rs4649203) variant was genotyped by TaqMan assay. Statistical analysis was performed including both diseases and a comprehensive list of patient clinical manifestations. RESULTS: The rs4649203-G (minor) allele was associated with SLE and RA occurrence and was shown to be a risk factor for serositis and anemia among SLE patients as well as a protective factor for rheumatoid vasculitis and rheumatoid nodules in RA patients, suggesting an association with a milder form of the disease. CONCLUSIONS: The IL28RA gene may contribute to SLE and RA susceptibility and to specific clinical manifestations of the diseases.