Our ultrasound today showed that the cystic hygroma is still large, and not getting any smaller. (Hard to tell if it was any bigger, though...) There was definitely fluid around the lungs and some swelling, so that isn't very good news. However, the heartbeat is still strong.
The doctor is not optimistic that the baby will survive beyond 18-22 weeks, so we are still in a holding pattern; praying for a miracle, hoping for the best, but aware of the prognosis and prepared for the worst.
Because the results from the CVS test were inconclusive, we had to have an amnio performed to obtain the karyotyping that we were originally looking to obtain.
(Amniocentesis is a procedure performed during pregnancy to examine a baby's chromosomes. Most often, an amniocentesis is done between 16-20 weeks of pregnancy. During this procedure, amniotic fluid is removed, using a hypodermic needle, for testing. The amniotic fluid contains cells that the baby has naturally shed. Cells and proteins within the amniotic fluid are examined in the lab to test for specific fetal disorders.)
The amnio went well, and was much less painful than the CVS a few weeks ago. They had to draw more fluid than they would for a typical amnio because we are having more than one test performed on the samples. We are having the standard chromosome analysis done, which will tell us (hopefully) that the number of chromosomes is correct and that they are, generally, in good shape.
Because the CVS indicates mosaic trisomy 15, they will look specifically at chromosome 15 to see of there is any evidence of 3 copies of it. Normally, they would sample about 50 cells to ascertain this information. But, a mosaicism can be present in only some areas, so they will test a larger number of cells to determine with more authority if it is, indeed, present in some or all cells. (Note- the test is not exact. There is no way to test all of the cells, so they choose a number and sample what they feel will be representative of the baby.)
They will also use the amnio sample to test for an UPD, uniparental disomy. Trisomy 15 is very rare, particularly this far along in pregnancy, so there is concern that if there is any Trisomy 15 detected that it could be due to an uniparental disomy. This is when a baby inherits one chromosome 15 from one parent and two chromosome 15's from the other parent. The cells recognize that there are too many 15's, so they cancel one out in order to be left with two, the appropriate number. In some cases, that can leave the baby with two sets of chromosome 15 from the same parent, which is uniparental disomy. There is a specific name for this if chromosome 15 comes from the father or mother. They will test the baby's chromosome 15 against each of our chromosome 15's to see if what the baby has is "normal."
The other DNA test they will perform is called CGH, comparative genomic hybridization. This will analyze the baby's DNA more closely to see if anything is has been deleted or added to a specific chromosome. This is how they typically test people for being carriers of commonly known genetic illnesses, such as Sickle Cell Anemia or Tay-Sachs Disease. This will allow them to diagnose the baby with any genetic illness that is already known and identifiable. This will not, however, allow them to tell us about things that are not known yet. For example, if we are both recessive carriers of something that causes cystic hygromas, they can only detect it if that illness is linked to a specific gene/chromosome. Because the genetic counselors are unaware of any specific genetic illness that causes cystic hygromas, it is likely that we will not find anything conclusive with the CGH analysis. But, to make sure we leave no stone unturned, we have opted to pursue it.
All of these test results (amnio, UPD and CGH) should be available in about two weeks. We go back for another ultrasound on Sept. 11 to see how the baby is doing and assess the prognosis once again. We are still praying that things can turn around and the baby can recover from this. While we know it is a long shot, we are not ready to give up.
Thank you all again for the positive thoughts, prayers and support! We are so grateful to everyone for all you are doing to help us through this. We will keep you posted.