Genetic Study In Male Infertility And Its Significance On Intacytoplasmic Sperm Injection And Preimplantation Genetic Diagnosis

Infertility describes couples who have never been able to become pregnant after at least 1 year of unprotected sex (intercourse). The incidence of infertility among Chinese fertile-aged couples is about 10%.30% caused by male factor,60% caused by female factor,10% caused by both. With the environment pollution increasing, more and more couples will suffer infertility. The factors leading male infertility include:chromosome aberrant, endocrine disease, genital system inflammatory, varicocoeles, abnormal sperm,immune infertility、male sexual function disorder. Genetic causes account for 10-15% of severe male infertility, including Klinefelter syndrome, Y chromosomal aberrations, Robertsonian translocation, reciprocal translocation, inversion and so on. As we know, the features of genetic disease are congenital, inhereditary, incure. It is important that how to do genetic counseling for the couples who suffer adverse pregnancy outcome and how to avoid inhereditary risk. This dissert contains three parts, they are:Common chromosome aberrants associated with infertility; Pregnancy outcome of ICSI with big Y chromosome; Study of preimplantation genetic diagnosis for couples suffering Y chromosome microdeletions and Robertsonian translocation.1. Relationship between chromosome aberrant and adverse pregnancy outcome Objective:To explore the relationship between adverse pregnancy outcomes and abnormal karyotypes. Methods:Karyotype the peripheral blood lymphocytes chromosomes of couples with recurrent pregnancy loss, embryo stops growing, stillbirth, fetal malformation and adverse pregnancy. Results:400 couples with abnormal pregancy underwent cytogenetic examination in which 60 persons were found with abnormal karyotypes, including 32 cases with large Y chromosome,9 with autosomatic heteromorphism,16 with reciprocal translocation,2 with inversion and 1 with 46,XX/47, XXX. Conclusions:Adverse pregnancy outcomes can occur when either of the couples has abnormal karyotypes. Karyotyping and genetic counseling are suggested for them2. Sperm quality and big Y chromosome influences pregnancy outcome of ICSI Objective:To explore the clinical effects of big Y chromosome karyotype in male sterility. Methods:Cytogenetics of patients with severe infertility was examined by culturing peripheral blood lymphocyte and showing chromosome bands using G analysis and ICSI treatment. Results:There were 10.91% male patients who have big Y chromosome karyotype and all of the male patients’sperms were abnormal. Among the cases of big Y chromosome karyotype patients, there were about 75.93% (41/54) cases of oligoasthenozoospermic and abnormal azoospermic,24.07%(13/54) cases of azoospermic, but normal form of sperm can be obtained in patients with azoospermia through testicular puncture;the ICSI cumulative pregnancy rate of patients with oligoasthenozoospermic and abnormal azoospermic is 53.85%, azoospermic is 48.78%; male birth rate is 47.83% (11/23), female is 52.17%(12/23),the both sex ratio were nearly 50%. Conclusions:Sperm abnormalities is associated with big Y chromosome. In big Y chromosome, the highly repetitive gene of DNA sequences is not completely inhibit spermatogenesis, its performance ratio in cases of oligoasthenozoospermic and abnormal azoospermic is three times to azoospermia. ICSI treatment with sperm obtained by puncture had no effect on pregnancy rate.3. Study of preimplantation genetics diagnosis Objectives:To investigate preimplantation genetic diagnosis (PGD) on two patients’ blastomeres with chromosome Y microdeletion and one patient with Robertsonian translocation. Methods:The patients were prepared for oocyte retrieval using standard controlled ovarian hyperstimulation protocols and then get ICSI or IVF. The embryos biopsy were carried out by mechanical method at 6-8 cell stage on day 3. Two blastomeres were removed from each embryo. The blastomeres of the first two patients were analyzed using fluorescence in situ hybridization (FISH) with three color commercial chromosomal probes special for chromosomes X, Y and 18. Female embryos with normal karyotype were transplanted on day 5. The blastomeres of the third patient were analyzed using FISH with two color commercial chromosomal probes special for chromosomes 13,21. The embryos with normal karyotypes or Robertsonian translocation carriers were transplanted on day 5 Results:Normal female embryos of the first two couples and normal embryos with normal karyotypes or Rob translocation carrier were transferred on day 5, respectively, but no pregnancy was achieved. Conclusion:Selected normal embryo transferring can prevent offsprings from suffering abnormal genes or chromosomes inherited from their father; It also can prevent the wife from getting recurrenc pregnant loss any more.