It is the diagnostic test that studies the number, size and structure of the chromosomes that make up each of the cells in a person and it is carried out by a blood test.
The human karyotype presents 23 pairs of chromosomes (46 chromosomes in total), amongst which there is a pair that determines sex, XX for women and XY for men.
A certain percentage of the population presents karyotype anomalies (translocations, inversions, deletions, etc…) which usually go unnoticed. These alterations become apparent when the couple wishes to have children and either infertility, repeat spontaneous abortions, or the birth of an affected child.
In these cases it is necessary to study these embryos to be able to identify those that are chromosomally normal. This is carried out by an In Vitro Fertilisation cycle with Preimplantation Genetic Diagnosis.
Also, in case of chromosomal rearrangements (except in Robertsonian translocations) is an informativity study must be carried out prior to the actual PGD. This study requires a blood sample from the carrier and is intended to develop a strategy that allows us to detect the chromosomal rearrangement. Once the informativity study (whose results are obtained over a period of 2-3 months) is completed, the IVF cycle and the PGD to select those embryos carrying the balanced translocation or the normal non-carriers ones can be started. If the genetic analysis is carried out by means of Array-CGH no prior informativity study will be required.
In all cases, to evaluate each case in a personalized way and in order to provide the couple with a better guidance about their prognosis, a consultation with our Biology Department will be required.