title: Intermediate and normal sized CGG repeat on the FMR1 gene does not negatively affect donor ovarian response.
abstract: BACKGROUND
  Fragile X syndrome is associated with low ovarian reserve and poor ovarian response. The aim of this study was to investigate whether CGG repeats on the fragile X mental retardation 1 (FMR1) gene have predictive value for ovarian response to stimulation with gonadotrophins and for clinical outcome in our oocyte donation program.
  
  
  METHODS
  Oocyte donor candidates were selected according to Instituto Bernabeu oocyte donation program requirements. Fragile X genetic screening was performed in 204 oocyte donors, defining 141 controls and 63 cases: 35-39 repeats (n = 34), 40-45 (n = 12) and >45 (n = 17). All the patients underwent ovarian stimulation using a GnRH antagonist protocol and received a GnRH agonist trigger. The main factors used to measure outcome were oocyte yields, days of stimulation, gonadotrophin dosages, biochemical pregnancy, ongoing pregnancy and miscarriage rates.
  
  
  RESULTS
  No differences between the study group and controls were reported in oocyte yields (17.5 versus 18.9) or days of stimulation (11.40 versus 9.82). The control group used significantly more gonadotrophin (2212 versus 1850 IU) than the study group. Clinical outcome was not affected by the CGG repeats on the FMR1 gene in oocyte donors.
  
  
  CONCLUSIONS
  No negative effect was observed for intermediate-sized CGG repeats on ovarian stimulation and clinical outcome using a non-confounding model of oocyte donation. These results disagree with previous studies performed on infertility patients. Owing to the present study, fragile X genetic screening should not be considered for prediction of response to ovarian stimulation.
authors.affiliation: IB Biotech, Avda. Albufereta, 31, 03016 Alicante, Spain. blledo@institutobernabeu.com
authors.forename: B
authors.initials: B
authors.lastname: Lledo
authors.forename: J
authors.initials: J
authors.lastname: Guerrero
authors.forename: J A
authors.initials: JA
authors.lastname: Ortiz
authors.forename: R
authors.initials: R
authors.lastname: Morales
authors.forename: J
authors.initials: J
authors.lastname: Ten
authors.forename: J
authors.initials: J
authors.lastname: Llacer
authors.forename: J
authors.initials: J
authors.lastname: Gimenez
authors.forename: R
authors.initials: R
authors.lastname: Bernabeu
mesh_terms: D000022:Abortion, Spontaneous / Q000235:genetics; D000328:Adult; D004305:Dose-Response Relationship, Drug; D005260:Female; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000737:chemistry / Q000235:genetics*; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists / Q000037:antagonists & inhibitors; D006062:Gonadotropins / Q000008:administration & dosage / Q000494:pharmacology; D006727:Hormone Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007247:Infertility, Female / Q000628:therapy; D008499:Medical Records; D018587:Oocyte Donation; D010060:Ovulation / Q000187:drug effects*; D010062:Ovulation Induction; D011247:Pregnancy; D011255:Pregnancy Maintenance; D018873:Pregnancy Rate; D012189:Retrospective Studies; D014019:Tissue Donors; D018911:Trinucleotide Repeats; D055815:Young Adult
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D007987:Gonadotropin-Releasing Hormone; D006062:Gonadotropins; D006727:Hormone Antagonists; C497683:FMR1 protein, human