title: A deletion mutation in GDF9 in sisters with spontaneous DZ twins.
abstract: A loss of function mutation in growth differentiation factor 9 (GDF9) in sheep causes increased ovulation rate and infertility in a dosage-sensitive manner. Spontaneous dizygotic (DZ) twinning in the human is under genetic control and women with a history of DZ twinning have an increased incidence of multiple follicle growth and multiple ovulation. We sequenced the GDF9 coding region in DNA samples from 20 women with DZ twins and identified a four-base pair deletion in GDF9 in two sisters with twins from one family. We screened a further 429 families and did not find the loss of function mutation in any other families. We genotyped eight single nucleotide polymorphisms across the GDF9 locus in 379 families with two sisters who have both given birth to spontaneous DZ twins (1527 individuals) and 226 triad families with mothers of twins and their parents (723 individuals). Using case control analysis and the transmission disequilibrium test we found no evidence for association between common variants in GDF9 and twinning in the families. We conclude that rare mutations in GDF9 may influence twinning, but twinning frequency is not associated with common variation in GDF9.
authors.affiliation: Genetic Epidemiology Laboratory, Queensland Institute of Medical Research, Brisbane, Australia. grantM@qimr.edu.au
authors.forename: Grant W
authors.initials: GW
authors.lastname: Montgomery
authors.forename: Zhen Zhen
authors.initials: ZZ
authors.lastname: Zhao
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Marsh
authors.forename: Renee
authors.initials: R
authors.lastname: Mayne
authors.forename: Susan A
authors.initials: SA
authors.lastname: Treloar
authors.forename: Michael
authors.initials: M
authors.lastname: James
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Martin
authors.forename: Dorret I
authors.initials: DI
authors.lastname: Boomsma
authors.forename: David L
authors.initials: DL
authors.lastname: Duffy
mesh_terms: D001315:Australia; D001483:Base Sequence; D055430:Bone Morphogenetic Protein 15; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D005838:Genotype; D055429:Growth Differentiation Factor 9; D006239:Haplotypes; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D015810:Linkage Disequilibrium; D008297:Male; D009154:Mutation; D009426:Netherlands; D010375:Pedigree; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017384:Sequence Deletion; D014429:Twins, Dizygotic / Q000235:genetics*
chemical_list: C525901:BMP15 protein, human; D055430:Bone Morphogenetic Protein 15; C525897:GDF9 protein, human; D055429:Growth Differentiation Factor 9; D036341:Intercellular Signaling Peptides and Proteins; D004247:DNA