S680N substitution of the follicle-stimulating hormone receptor is a common polymorphism not associated with spontaneous human twinning.
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.
Hasbargen
U
U
Department of Obstetrics and Gynaecology, Klinikum der Universitaet Muenchen-Grosshadern, Marchioninistr. 15, D-81377 Munich, Germany. hasbargen@gyn.med.uni-muenchen.de
Thaler
C J
CJ
Ruebsamen
H
H
Fuchshuber
S
S
Lohse
P
P
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*
D017931:DNA Primers; D020033:Protein Isoforms; D011962:Receptors, FSH