PGT-A

The test involves analyzing the genetic material of an embryo isolated from trophoectoderm cells taken on the fifth day, the part from which the placenta develops in the later stages of pregnancy. The embryo’s DNA is tested in a genetics laboratory using NGS (next-generation sequencing) technology. After receiving the test results, specialists decide which embryos can be used in the IVF procedure. The PGT-A test makes it possible to select a genetically healthy embryo for transfer. This creates a better chance that the in vitro fertilization procedure will be successful and the baby that will be born will be healthy.

We speak of aneuploidy when the basic set of chromosomes characteristic of a species, or karyotype, is enriched or lacking at least one chromosome. Thus, the cells of such an organism contain a higher or lower number of chromosomes relative to the normal state. Aneuploidies most often arise from the erroneous divergence of chromosomes during cell division (meiosis). Their presence is unfortunately associated with the occurrence of serious birth defects in the child, but most often results in spontaneous miscarriage.

Examples of aneuploidy

Trisomy: is the presence of an extra third chromosome in a given homologous pair (in genetics is denoted as 2n+1). In humans, trisomy of chromosome 21 is the cause of Down syndrome, chromosome 18 is the cause of Edwards syndrome, while 13 is the cause of Patau syndrome.

Monosomy: is the absence of one chromosome from a given pair (denoted as 2n-1 in genetics). Monosomy often results in the death of the embryo at an early developmental stage (lethal mutation). In humans, the most common example of monosomy is monosomy of the X chromosome (X0 in the karyotype) responsible for Turner syndrome.