New developments on genetic technology are providing genetic explorations on embryos, created as test tube baby. This method is called Preimplantation Genetic Diagnosis (PGD). Preimplantation Genetic Diagnosis (PGD) is realized by getting 1 or 2 cells from the embryos, developed by insemination of oocyte and sperm cells in the laboratory.

Specific methods are used on these cells and it is possible to diagnose structural chromosome distortions and gene diseases (Thalassaemia, Sickle Cell Anemia, Cystic Fibrosis etc). Therefore it is also possible to transfer healthy embryos to the mother and to have healthy babies.

The situations where PGT should be advised.

• The diagnosis of the existence of  structural or numerical chromosomes abnormalities on mother/father
• If both mother and father have the same single gene disorder.
• Either mother or father has one-gene disease
• On couples who are practiced assisted reproductive techniques (ART)

          - Advanced maternal age (≥37)
          - Recurrent pregnancy loss
          - Severe male infertility
          - Recurrent implantation failure

PGT is implemented for having healthy babies in the families who have kids born with genetic diseases. It is also possible to practice this method on couples using assisted reproductive techniques such as test tube baby or microinjection. PGT is the significant methods for defining chromosome abnormelities that would probably occur at babies whose mothers are over 37 of age and are accepted to use methods of test tube baby and microinjection on them.

The possibility of conveying the distortions to embryo by oocyte/sperm cells on the cases which are diagnosed anomaly (45,X, 47,XXY, etc.) on sexual chromosomes is  high. These risks change (65%-80%) according to the type of translocations on couples having balanced structural chromosome distortions (translocation). Therefore chromosome analysis should absolutely be done on couples wanting test tube baby. And those couples should also be given consultancy, prenatal and preimplantation genetic diagnosis be offered.

Explorations made on couples suffering recurrent pregnancy loss show that they have different percentage of chromosome distortions, for the first three-months 50%-60%, for the second three-months 20%-25%, the third three-month 5%-10%). Although many couples have normal chromosome structures, they have defects on mosaic or segregation mechanism covering nsust breeding cells. Whereas no symptoms have found on couples, those defects may also observed on embryos which can be found and eliminated by PGT.

Besides although supporting by assisted reproductive techniques and giving embryos in good quality, some couples may not get pregnant because of genetic defects on their embryos.

Even if PGD is used on couples wanting test tube baby because of the infertility problems, the real aim for PGT is to define genetic diseases at the stage of embryo. Because of the fact that couples convey their disease to the child at different proportions, defining the disease on couples before getting late is important for having healthy babies. In today’s world it is possible to define many genetic diseases at the stage of embryo growth.

By the technique of DNA sequencing analysis permanent changes called mutations causing diseases is detected more precisely and effectively. At this system DNA samples are marked by different colors. After that these samples are defined by a laser reader and transferred into the computer. So, genetic malfunctions have been diagnosed. Nowadays Βeta Thalassemia, Sickle Cell Anemia, Cystic Fibrosis, Hemophilia mutations are already transcribed. By using array analysis methods instead of using other DNA analysis make it easier to diagnose the majority of mutations causing diseases.

Via this method DNA of the cell obtaining embryos of couples who are suffering genetic diseases are multiplied using “single cell pcr” method, and the area of the gene causing the disease are deciphered by array analysis method. In result embryos having genetic distortions are eliminated and healthy babies having no genetic defects are ensured to born. With the technique of DNA sequncing analysis, defining genetic diseases on muscular diseases such as Βeta Thalassemia, Sickle Cell Anemia, Cystic Fibrosis, Hemophilia and Duchenne/Becker Muscular Dystrophy (DMD/BMD)are certainly possible.