Recent developments of techniques in molecular and cellular genetics enable couples to have healthy children, free from genetic and chromosomal abnormalities. One technique called PGD (pre-implantation genetic diagnosis) has been applied in the past few years by fertility experts, in combination with in vitro fertilization; it allows detection of genetic diseases before the embryo is transferred to the uterine cavity.

 

What do you need to know about the chromosomes of the embryo?

 

The genetic material, which is transmitted from one generation to the other, and which is required for any organism to develop normally, is organized in special structures in the nucleus of each cell (the chromosomes). During  fertilization, the nucleus of the spermatozoon (bearing 23 male chromosomes), is combined with the nucleus of the oocyte (bearing 23 female chromosomes), to create an cell with a total of 46 chromosomes. This is the beginning of your child's existence. The lack or the excess of one or more chromosomes in the cells of an organism is called aneuploidy or numerical chromosomal abnormality. About 50% of automatically aborted fetuses have major chromosomal abnormalities. Numerical chromosomal abnormalities are associated with human genetic syndromes such as, for example, trisomy 21 (or Down syndrome). Monogenic disorders are another type of genetic disorder, associated with diseases such as cystic fibrosis and thalassemia.