Abstract for presentation at 11th International Congress of Human Genetics

Follicular fluid - a novel source of cells to detect gonadal chromosome mosaicism

  • Dr Firuza Parikh, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Dr Prochi Madon, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Ms Arundhati Athalye, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Mr Suresh Dhumal, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Mr Mahadev Kawle, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Mr Nandkishor Naik, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Mr Dattatray Naik, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India
  • Dr Suparna Nadkarni, Dept. of Assisted Reproduction and Genetics, Jaslok Hospital and Research Centre, Mumbai., India

    • Purpose: To establish a rapid technique to detect gonadal chromosome mosaicism in women undergoing IVF.
    Methods: Fluorescence in-situ hybridization (FISH) was carried out on cells present in follicular fluid after oocyte retrieval. Samples were analysed using Vysis Aneuvysion CEP probes for chromosomes X, Y and 18, a Zeiss fluorescence microscope and Metasystems software. The probe for chromosome 18 was used as an internal control to check the hybridization efficiency and rule out triploidy or tetraploidy. About 100-200 interphase nuclei were analyzed per sample. This is an ongoing study initiated in 2002. A total of 731 adequate samples were available for analysis.
    Results: Normal diploid signals for the X chromosome were seen in 100% cells in 71% samples, while 18% samples had only 1-2% cells with either X or XXX and were considered as lying within the cut-off range. Atleast 5% X or XXX mosaicism was seen in 4% samples. This group was considered significant due to a very poor IVF outcome, where a majority of women did not conceive and those who aborted had a high rate of fetal aneuploidy. The remaining 7% samples had 3-4% mosaicism and a moderate outcome of IVF. Trisomy 16 was detected in the products of conception of a woman exhibiting 20% XXX and 10% XO cells. Low-grade mosaicism was also demonstrated by FISH in the buccal and urine cells in some of these women and confirmed on karyotyping from blood.
    Conclusions: Follicular fluid is a novel source of gonadal cells for detection of low-grade mosaicism in the ovaries. All women with unexplained infertility undergoing IVF could be studied to determine the chances of a successful pregnancy. If there is evidence of gonadal mosaicism, the chances of a live birth could be low. Mosaicism detected rapidly by FISH on follicular fluid cells can be one more indication for preimplantation genetic diagnosis (PGD) in the same and subsequent cycles. This is an ongoing study and needs confirmation from other laboratories.

    Conference Organiser - ICMS Pty Ltd