|
PGD in Italy: 1PB Testing
Preconception genetic diagnosis
Since March 2004, a new law regulates IVF techniques in
Italy, imposing very strict conditions (Benagiano and
Gianaroli, 2004). This law limits to three the number of
oocytes that can be fertilized during each IVF treatment and
obligates the simultaneous transfer of all three possible
embryos. Oocyte cryopreservation is allowed while freezing
of spare embryos is prohibited. Moreover, the use of IVF
techniques is restricted to sterile couples, thus precluding
the access to assisted reproductive techniques to fertile
couples who are at risk for transmitting severe genetic
diseases to their offspring.
According to the text of the new regulation, technically PGD
would be not illegal, because “clinical and experimental
research on embryos is permitted only for therapeutic and
diagnostic purposes”. However, the obligation for transfer
of all embryos generated after oocytes’ fertilization,
including those resulting affected by the genetic disease,
makes PGD unfeasible. Afterwards, the Ministry of Health
Guidelines has clarified that PGD on embryos is forbidden
for any purposes.
Therefore, the only option for couples at high genetic risk
for prevention of genetic diseases is 1PB testing (so called
Preconception genetic diagnosis) before oocyte
fertilization, provided that they are also infertile.
In preconception genetic diagnosis, ICSI can be performed
only after genetic diagnosis of oocytes. Moreover, results
of genetic testing must be achieved within a reasonable time
to prevent in-vitro ageing of the oocytes. In fact, there is
only a very narrow window of time available for
preconception genetic diagnosis, but if the 1PB biopsy is
performed soon after oocyte collection (Magli et al., 2006)
and follows a rapid diagnostic protocol, oocyte insemination
could be carried out according to the results of the genetic
analysis.
We have overcome to the time restriction problem by
developing a rapid protocol for diagnosis of single gene
mutations of maternal origin, capable of producing results
within just 4 hours, making it realistic to fertilize the
oocytes predicted to be free of mutation within a timeframe
compatible with a late ICSI (6 h after oocytes collection).
Next :
Technical description of the procedure
|
