Homozygosity for the rs9939609T allele of the FTO gene may have protective effect on becoming overweight in survivors of childhood acute lymphoblastic leukaemia

Abstract

Approximately 20% of adolescents and children in Europe are overweight, and 30% of those who are overweight actually fulfill the criteria of obesity (Branca et al. 2007). The prevalence of obesity in survivors of acute lymphoblastic leukaemia (ALL) is 16 to 57% (Gregory and Reilly 2004). Among others, cranial radiotherapy (CRT) and genetic factors have been implicated as risk factors of overweight/obesity (Ross et al. 2004; Chow et al. 2007). The fat mass and obesity associated gene (FTO) has been recently found to contribute to the risk of obesity. Polymorphism of rs9939609 T>A was associated with an increased BMI in children aged ≥7 years. Individuals homozygous for A allele at rs9939609 constituted 16% of the population and population risk was 20.4% for obesity and 12.7% for overweight (Frayling et al. 2007). The high-risk FTO haplotype yielded a proportion of attributable risk of 22% for uncomplicated obesity in adults and children of European ancestry (Dina et al. 2007). Therefore, the influence of rs9939609 T>A polymorphism of FTO gene on overweight in leukaemia survivors was studied. A total of 191 patients were genotyped for the above genetic variant. Significant negative association between the rs9939609T allele and prevalence of overweight status was found in a subset of patients treated with CRT. Patients who receive CRT and are carriers of this variant may be protected from becoming overweight.