RESUMO
OBJECTIVE: The alpha(2)-adrenergic receptors are involved in the effects of catecholamines on energy metabolism. Of three known subtypes with differential expression, alpha(2A)-adrenergic receptors are also localized in adipose tissue where they counteract the lipolytic activity of beta-adrenergic receptors. This study was undertaken to assess whether variants in the alpha(2A)-adrenergic receptor gene are associated with body weight. DESIGN AND METHODS: Single strand conformation polymorphism (SSCP) screening and subsequent sequencing were applied to determine genetic variants in DNA samples from individuals with obesity, those of normal weight and those underweight. RESULTS: Analysis of the coding region resulted in the identification of an 18 bp deletion, with no other mutation found. Of 429 genotyped subjects, 7 carried the deletion, with no significant differences between lean and obese subjects. A previously identified polymorphism in the promoter of the alpha(2A)-adrenergic receptor gene also did not show an association with any of the tested body weight categories. CONCLUSION: Our data suggest that variants in the alpha(2A)-adrenergic receptor gene are unlikely to contribute to the predisposition for the lean or obese state.
Assuntos
Peso Corporal/genética , Variação Genética/genética , Receptores Adrenérgicos alfa 2/genética , Deleção de Sequência/genética , Adolescente , Adulto , Índice de Massa Corporal , Criança , Estudos de Coortes , Análise Mutacional de DNA , Feminino , Frequência do Gene/genética , Predisposição Genética para Doença , Testes Genéticos , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/genética , Polimorfismo Conformacional de Fita Simples , Regiões Promotoras Genéticas/genética , Magreza/genéticaRESUMO
The peroxisome proliferator-activated receptor-gamma2 (PPARgamma2) is almost uniquely expressed in adipose tissue and is of major importance for fat cell differentiation and lipid metabolism. This study was undertaken to assess whether two missense variants in the PPARgamma2 gene are associated with early-onset obesity. A previously described polymorphism encoding for an amino acid exchange in codon 12 (Pro12Ala) was detected with allele frequencies of 0.13 in 296 markedly obese children and adolescents and 0.14 in 130 lean individuals. A Pro115Gln variant, which had been linked to obesity in Germans in a previous association study, was not detected in any of our obese or lean subjects, who are also of German origin. We conclude from our data that these two variants in the PPARgamma2 gene are unlikely to contribute to the high prevalence of early-onset obesity.
