RESUMO
BACKGROUND: Patients with anorexia nervosa restricting type (AN-R) often develop bulimic symptoms and crossover to AN-binge eating/purging type (AN-BP), or to bulimia nervosa (BN). We have reported earlier that genetic variants of an orexigenic peptide ghrelin are associated with BN. Here, the relationship between a ghrelin gene variant and the rate of change from AN-R to other phenotypes of eating disorders (EDs) was investigated. METHODS: Participants were 165 patients with ED, initially diagnosed as AN-R. The dates of their AN-R onset and changes in diagnosis to other subtypes of ED were investigated retrospectively. Ghrelin gene 3056 T-->C SNP (single nucleotide polymorphism) was genotyped. Probability and hazard ratios were analyzed using life table analysis and Cox's proportional hazard regression model, in which the starting point was the time of AN-R onset and the outcome events were the time of (i) onset of binge eating, that is, when patients changed to binge eating AN and BN and (ii) recovery of normal weight, that is, when patients changed to BN or remission. RESULTS: Patients with the TT genotype at 3056 T-->C had a higher probability and hazard ratio for recovery of normal weight. The ghrelin SNP was not related with the onset of binge eating. CONCLUSION: The 3056 T-->C SNP of the ghrelin gene is related to the probability and the rate of recovery of normal body weight from restricting-type AN.
Assuntos
Anorexia Nervosa/genética , Grelina/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Idade de Início , Anorexia Nervosa/diagnóstico , Anorexia Nervosa/epidemiologia , Transtorno da Compulsão Alimentar/diagnóstico , Transtorno da Compulsão Alimentar/epidemiologia , Transtorno da Compulsão Alimentar/genética , Índice de Massa Corporal , Bulimia/genética , Bulimia Nervosa/diagnóstico , Bulimia Nervosa/epidemiologia , Bulimia Nervosa/genética , Criança , Feminino , Genótipo , Humanos , Peso Corporal Ideal/genética , Japão/epidemiologia , Pessoa de Meia-Idade , Fenótipo , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Fatores de Tempo , Adulto JovemRESUMO
Previous investigations have suggested that ghrelin, an endogenous orexigenic peptide, is involved in the pathology of eating disorders. We conducted a study to determine whether any preproghrelin gene polymorphisms are associated with eating disorders. Three hundred thirty-six eating disorder patients, including 131 anorexia nervosa (AN)-restricting types (AN-R), 97 AN-binge eating/purging types (AN-BP) and 108 bulimia nervosa (BN)-purging types (BN-P), and 300 healthy control subjects participated in the study. Genotyping was performed to determine the polymorphisms present, and with this information, linkage disequilibrium (LD) between the markers was analyzed and the distributions of the genotypes, the allele frequencies, and the haplotype frequencies were compared between the groups. The Leu72Met (408 C > A) (rs696217) polymorphism in exon 2 and the 3056 T > C (rs2075356) polymorphism in intron 2 were in LD (D' = 0.902, r2 = 0.454). Both polymorphisms were significantly associated with BN-P (allele-wise: P = 0.0410, odds ratio (OR) = 1.48; P = 0.0035, OR = 1.63, for Leu72Met and 3056 T > C, respectively). In addition, we observed a significant increase in the frequency of the haplotype Met72-3056C in BN-P patients (P = 0.0059, OR = 1.71). Our findings suggest that the Leu72Met (408 C > A) and the 3056 T > C polymorphisms of the preproghrelin gene are associated with susceptibility to BN-P.
