title: S680N substitution of the follicle-stimulating hormone receptor is a common polymorphism not associated with spontaneous human twinning.
abstract: OBJECTIVE
  To determine the influence of the A307/S680 and T307/N680 isoforms of the follicle-stimulating hormone receptor (FSHR) gene on the incidence of spontaneous human twinning.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  Departments of Obstetrics and Gynecology and of Clinical Chemistry-Grosshadern, University Hospital Munich, Germany.
  
  
  METHODS
  Fifty-four mothers with dichorionic twin pregnancies and 92 singleton mothers as controls, who had conceived without assisted reproduction.
  
  
  METHODS
  Exon 10 of the FSHR gene was screened for the G2105A/S680N mutation.
  
  
  METHODS
  Amplification of genomic DNA by the polymerase chain reaction followed by restriction fragment length polymorphism analysis.
  
  
  RESULTS
  Allele frequencies for the G2105A/ S680N substitution of the FSHR in twin mothers were not different from those of controls (genotype (isoform) [twins vs. controls]: G/G (S/S) [24.1% vs. 22.3%]; A/G (N/S) [57.4% vs. 55.4%]; A/A (N/N) [18.5% vs. 22.3%]). Subgroup analysis of women with three or more successful pregnancies gave a similar result (G/G (S/S) [17.7% vs. 13.7%]; A/G (N/S) [64.7% vs. 63.6%]; A/A (N/N) [17.6% vs. 22.7%]). There was no correlation between FSHR isoform and twinning.
  
  
  CONCLUSIONS
  The S680N substitution of the follicle-stimulating hormone receptor is a common polymorphism not associated with spontaneous human twinning.
authors.affiliation: Department of Obstetrics and Gynaecology, Klinikum der Universitaet Muenchen-Grosshadern, Marchioninistr. 15, D-81377 Munich, Germany. hasbargen@gyn.med.uni-muenchen.de
authors.forename: U
authors.initials: U
authors.lastname: Hasbargen
authors.forename: C J
authors.initials: CJ
authors.lastname: Thaler
authors.forename: H
authors.initials: H
authors.lastname: Ruebsamen
authors.forename: S
authors.initials: S
authors.lastname: Fuchshuber
authors.forename: P
authors.initials: P
authors.lastname: Lohse
mesh_terms: D000483:Alleles; D019943:Amino Acid Substitution; D016022:Case-Control Studies; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D006801:Humans; D011110:Polymorphism, Genetic; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000235:genetics*; D020033:Protein Isoforms / Q000235:genetics; D011962:Receptors, FSH / Q000235:genetics*; D014429:Twins, Dizygotic / Q000235:genetics*
chemical_list: D017931:DNA Primers; D020033:Protein Isoforms; D011962:Receptors, FSH