For reciprocal translocations, we request blood from the individual with the translocation as well as from the normal partner. This allows for preliminary analyses to be performed with probes to confirm that PGD can be done. Once the blood samples are received, probes are ordered and the preliminary work can be performed.

A customized set of PGD probes will be selected depending on the particular balanced structural rearrangement.

All possible unbalanced rearrangements will be reviewed before a couple begins the IVF process to ensure correct identification of balanced and unbalanced complements.

Typically FISH probes are used for the chromosomes involved in the rearrangement.

For each of the numbered chromosomes tested two signals (or lights) should appear. An example of a normal FISH test for a balanced structural rearrangement.

If the individual with the translocation is a male, we recommend FISH analyses of sperm prior to undergoing PGD.

Determination of the percentage of unbalanced sperm will allow for estimates of the percentage of embryos that will be unbalanced, and therefore, determination of whether PGD is the best option.

Next : Advantages of PGD for translocation