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