title: FTO gene is related to obesity in Chilean Amerindian children and impairs HOMA-IR in prepubertal girls.
abstract: OBJECTIVE
  The objective of this study was to investigate the allelic frequency of the fat mass and obesity-associated (FTO) gene (rs9939609) and its influences on obesity and metabolic risk biomarkers in a cohort of normal weight and obese Chilean children determining its ethnicity.
  
  
  METHODS
  A total of 136 normal weight children and 238 obese children (between 6 and 11 yr old) from an urban setting were recruited for this case-control study. The children were classified as normal weight [body mass index (BMI) ≥ 5th and < 85th percentiles] or obese (BMI >95th percentile), according to the international age- and gender-specific percentiles defined by the Center for Disease Control and Prevention. The analysis of serum markers was carried out using commercial kits. The FTO polymorphism was determined through a high-resolution melting enabled real time polymerase chain reaction. Ethnicity was determined by analyzing mitochondrial DNA by the restriction fragment length polymorphism method.
  
  
  RESULTS
  As much as 85% of the cohort was Amerindian. The minor A allele of rs9939609 was associated with obesity (odds ratio (OR): 1.422 [95% confidence interval (CI) 1.068-1.868] p = 0.015), calculated using an additive model. In sex-stratified analysis we found that the risk variant (A) of rs9939609 was associated with a higher homeostasis model of assessment for insulin (HOMA-IR) in prepubertal obese girls. In male carriers of the A allele, HOMA-IR showed no further deterioration than that already associated with obesity.
  
  
  CONCLUSIONS
  In summary, we confirm the association of the FTO gene single-nucleotide polymorphism rs9939609 with obesity in Chilean Amerindian children. Furthermore we show an association between the risk allele (A) and insulin resistance-related markers in prepubertal obese girls.
authors.affiliation: Departamento de Bioquímica Clínica, Facultad de Farmacia, Universidad de Concepción, Concepción, Chile.
authors.forename: Benilde
authors.initials: B
authors.lastname: Riffo
authors.forename: Sylvia
authors.initials: S
authors.lastname: Asenjo
authors.forename: Katia
authors.initials: K
authors.lastname: Sáez
authors.forename: Claudio
authors.initials: C
authors.lastname: Aguayo
authors.forename: Isabel
authors.initials: I
authors.lastname: Muñoz
authors.forename: Paulina
authors.initials: P
authors.lastname: Bustos
authors.forename: Ca
authors.initials: C
authors.lastname: Celis-Morales
authors.forename: Jenny
authors.initials: J
authors.lastname: Lagos
authors.forename: Jorge
authors.initials: J
authors.lastname: Sapunar
authors.forename: Natalia
authors.initials: N
authors.lastname: Ulloa
mesh_terms: D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO; D016022:Case-Control Studies; D002648:Child; D002677:Chile; D005260:Female; D006706:Homeostasis; D006801:Humans; D007199:Indians, South American / Q000235:genetics*; D007333:Insulin Resistance / Q000235:genetics*; D008954:Models, Biological; D009765:Obesity / Q000235:genetics*; D011506:Proteins / Q000235:genetics*
chemical_list: D011506:Proteins; D000071516:Alpha-Ketoglutarate-Dependent Dioxygenase FTO; C526492:FTO protein, human