title: Fatty-acid binding protein 4 gene polymorphisms and plasma levels in children with obstructive sleep apnea.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is associated with increased risk for metabolic syndrome in both adults and children. In adults with OSA, serum levels of fatty acid binding protein 4 (FABP4) are elevated and associated with the degree of metabolic insulin resistance, independent of obesity. Therefore, we assessed plasma FABP4 levels and FABP4 allelic variants in obese and non-obese children with and without OSA.
  
  
  METHODS
  A total of 309 consecutive children ages 5-8years were recruited. Children were divided into those with OSA and without OSA (NOSA) based on the apnea-hypopnea index (AHI). Subjects were also subdivided into obese (OB) and non-obese (NOB) based on BMI z score. Morning fasting plasma FABP4 levels were assayed using ELISA, and 11 single-nucleotide polymorphisms (SNPs) within the FABP4 region were genotyped.
  
  
  RESULTS
  Morning plasma FABP4 levels were increased in all children with OSA, even in NOB children. However, plasma FABP4 levels were strongly associated with BMI z score. Of the 11 SNPs tested, the frequency of rs1054135 (A/G) minor allele (A) was significantly increased in OSA. This SNP was also associated with increased plasma FABP4 levels in both OSA and obese subjects. The minor allele frequency of all other SNPs was similar in OSA and NOSA groups.
  
  
  CONCLUSIONS
  Childhood obesity and OSA are associated with higher plasma FABP4 levels and thus promote cardiometabolic risk. The presence of selective SNP (e.g., rs1054135) in the FABP4 gene may account for increased plasma FABP4 levels in the context of obesity and OSA in children.
authors.affiliation: Department of Pediatrics, Comer Children's Hospital, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Bharat
authors.initials: B
authors.lastname: Bhushan
authors.forename: Abdelnaby
authors.initials: A
authors.lastname: Khalyfa
authors.forename: Karen
authors.initials: K
authors.lastname: Spruyt
authors.forename: Leila
authors.initials: L
authors.lastname: Kheirandish-Gozal
authors.forename: Oscar Sans
authors.initials: OS
authors.lastname: Capdevila
authors.forename: Rakesh
authors.initials: R
authors.lastname: Bhattacharjee
authors.forename: Jinkwan
authors.initials: J
authors.lastname: Kim
authors.forename: Brendan
authors.initials: B
authors.lastname: Keating
authors.forename: Hakon
authors.initials: H
authors.lastname: Hakonarson
authors.forename: David
authors.initials: D
authors.lastname: Gozal
mesh_terms: D002648:Child; D002675:Child, Preschool; D050556:Fatty Acid-Binding Proteins / Q000097:blood / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D005838:Genotype; D006801:Humans; D008297:Male; D009765:Obesity / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D017286:Polysomnography; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood / Q000453:epidemiology* / Q000235:genetics*
chemical_list: C493410:FABP4 protein, human; D050556:Fatty Acid-Binding Proteins