title: A quantitative trait locus on chromosome 22 for serum leptin levels adjusted for serum testosterone.
abstract: OBJECTIVE
  Studies have reported the existence of marked sexual dimorphism in serum leptin levels in humans with women having approximately two to three times the levels of men. We have shown that this sexual dimorphism has a strong genetic component arising from a genotype by sex interaction, but adjusting leptin levels for testosterone eliminates this interaction. Because interactions such as genotype x sex can confound the detection of quantitative trait loci (QTLs), we wanted to determine if there are QTLs associated with the expression of leptin adjusted for testosterone.
  
  
  METHODS
  We performed a genome-wide scan using multipoint linkage analysis and implemented a general pedigree-based variance-component approach to identify genes with measurable effects on variation in leptin levels independent of testosterone in 318 Mexican Americans from the San Antonio Family Heart Study.
  
  
  RESULTS
  We detected significant evidence of linkage (log of the odds ratio = 3.44) for a QTL on chromosome 22.
  
  
  CONCLUSIONS
  Given these results, we hypothesize that a QTL on chromosome 22 may influence the level of leptin adjusted for testosterone.
authors.affiliation: Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA. lisa.martin@chmc.org
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Martin
authors.forename: Michael C
authors.initials: MC
authors.lastname: Mahaney
authors.forename: Laura
authors.initials: L
authors.lastname: Almasy
authors.forename: James E
authors.initials: JE
authors.lastname: Hixson
authors.forename: Shelley A
authors.initials: SA
authors.lastname: Cole
authors.forename: Jean W
authors.initials: JW
authors.lastname: MacCluer
authors.forename: Cashell E
authors.initials: CE
authors.lastname: Jaquish
authors.forename: John
authors.initials: J
authors.lastname: Blangero
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Comuzzie
mesh_terms: D000328:Adult; D002892:Chromosomes, Human, Pair 22; D005260:Female; D005838:Genotype; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D020738:Leptin / Q000097:blood*; D008126:Lod Score; D008297:Male; D008800:Mexico / Q000208:ethnology; D008875:Middle Aged; D010641:Phenotype; D040641:Quantitative Trait Loci / Q000235:genetics*; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood*
chemical_list: D020738:Leptin; D013739:Testosterone