Trisomy 13, also known as Patau’s syndrome, and Trisomy 18, also known as Edwards’ syndrome, are conditions where the presence of chromosomal abnormalities generally result in severe mental retardation and physical disfigurement.
Children born with either condition usually die within the first year of life. Parents of these children often
undergo a tubal ligation surgery for fear that their next child would be
affected with the same disorder.
Some of these parents, after much consideration and consultation with
experts, recognize that this condition may not occur in future
pregnancies. A tubal reversal is an option that will help these couples
bear children again. Woman who are interested in a tubal reversal should be very aware of all the possible problems which may arise, especially if they are over the age of 40 . Although a tubal reversal may be the best option, these women should also explore other alternatives such as adoption. While the main concern will be the related risk of a trisomy 13 or trisomy 18, the fact is that the risk is the same for patients who undergo a tubal reversal as for those in the general population.
What is the possibility that parents with a child with trisomy 13 or trisomy 18 will have another baby with the same problem?
There is very little possibility that the parents of a child with trisomy 13 or trisomy 18 will have another baby with the same problem. The likelihood of this occurrence is only 1% or less, as the majority of these cases are not inherited. Trisomy 13 and trisomy 18 mostly occur secondary to random events occurring during sperm and egg cell formation. The risk is different, however, in cases of translocation and mosaic trisomies of chromosomes 13 and 18. The chromosomal abnormalities present in these conditions have varied genetic implantation risks.
The risk of having children affected with these conditions is higher among mothers of advanced age. The average age of a mother who has a baby with trisomy 13 is 32 years old. For trisomy 18 the average age is 31. The risk increases with each added year.
The physician will perform a karyotype to analyze the chromosomes of an infant suspected of having trisomy 13 or 18. A Karyotype is performed by extracting blood fromthe newborn. Results give significant information to parents about their risk in future pregnancies. The physician may also refer parents for genetic testing to determine if the condition was a translocation or a mosaic type. This determination will help predict the risk of recurrence in future pregnancies.
Is there a therapy which can cure or prevent trisomy 13 or trisomy 18?
Gene therapy has done immensely well over the past few decades in many fields, but there are still no specific therapies available to avert the
erratic chromosomal events that cause trisomy 13 or trisomy 18.
If I have a child with trisomy 13 or 18, will IVF be a better choice for me than a Tubal Reversal?
The major advantage of IVF over Tubal Reversal is the ability for Pre-implantation Genetic Determination. With IVF, the embyo can be Karyotyped prior to implantation to ensure that the child will not have trisomy 13 or 18. A patient who has a Tubal Reversal will not have this same luxury as the embryo produced from a Tubal Reversal pregnancy will not be selected out for either of these abnormalities.