one thing i haven't really gone into detail on here, has been jonathan's amniocentesis results. of course, the amnio confirmed full trisomy 13. trisomy 13 just in and of itself would have been by chance (up to 1 in 25,000.) but the genetic counselor told us that the trisomy 13 that jonathan has was by way of something called translocation, which means his extra 13th chromosomes were actually attached to the 14th chromosomes. this attachment between the 13th and 14th chromosomes is the most common translocation found and it's called Robertsonian Translocation. i have included pictures of chromosomes that show normal, trisomy 13, and trisomy 13 with the translocation for your understanding, below:
normal male chromosomes (above)
Male with Trisomy 13, Robertsonian Translocation (above, look at the #14) this is what Jonathan has.
the fact that jonathan has a translocation at all concerned us greatly, because it usually means that either greg or i would be a carrier of the robertsonian translocation. if so, it would mean that our chances of having another trisomy 13 baby were much higher. i can't explain this well, so here is part of an article that describes it very clearly:
"Individuals with Robertsonian translocations can have these as the result of a spontaneous event occurring during the meiosis (in either parent) that produced the egg or sperm from which they were made, shortly after conception, or from the inheritance of the same from one of their parents. Robertsonian translocations are present in approximately 1/1,000 newborns. Individuals with balanced translocations are usually healthy and often unaware of their condition, especially if there is no prior family history that has led to the diagnosis, and often their chromosomal ‘abnormality’ will not be discovered until they have difficulty having children. The problem arises when individuals with Robertsonian translocations try to make gametes [sperm/eggs.] In the case of someone who has a balanced 13;14 translocation, the possible gametes she will produce may contain:
1) One free copy of chromosome (chr) 13 and one free copy of chr 14.
2) The translocation (chr 13;14) chromosome alone (which contains one copy of chr 13 fused with one copy of chr 14).
3) Chr 13;14 + one free copy of chr 13 (essentially, a gamete with TWO copies of chr 13 rather than just one).
4) One free copy of chr 13 (and NO copy of chr 14).
5) Chr 13;14 + one free copy of chr 14 (TWO copies of chr 14 rather than just one).
6) One free copy of chr 14 (and NO copy of chr 13).
Obviously, 3 through 6 are gametes that have the incorrect number of chromosomes (either too little or too much genetic material). When these gametes get together with the, presumably, ‘normal’ gametes from her partner (which contain one free copy of chromosome 13 and 14), the following possibilities result (in the same order as above):
1) Two free copies of chr 13 + two free copies of chr 14 = NORMAL
2) Chr 13;14 + one free copy of chr 13 + one free copy of chr 14 = translocation ‘carrier’ (just like Mom) with NORMAL TOTAL amount of genetic material
3) Chr 13:14 + TWO free copies (one EXTRA from Mom and one from Dad) of chr 13 + one free copy (from Dad) chr 14 = TRISOMY 13
4) Two free copies chr 13 (one from Mom and one from Dad) + ONE free copy of chr 14 (NONE from Mom and one from Dad) = MONOSOMY 14 (miscarriage)
5) Chr 13:14 + one free copy of chr 13 (from Dad) + TWO free copies (one EXTRA from Mom and one from Dad) chr 14 = TRISOMY 14 (miscarriage)
6) ONE free copy chr 13 (NONE from Mom and one from Dad) + two free copies of chr 14 (one from Mom and one from Dad) = MONOSOMY 13 (miscarriage.)
Therefore, mathematically, she has only a 2 in 6 (33.3%) chance of having a baby that has the right TOTAL amount of genetic material; one of these will be entirely chromosomally normal and the other will be a translocation ‘carrier’ just like herself. Two-thirds of her babies are at risk for being chromosomally ABNORMAL.But, as I mentioned at the outset, things are not quite that simple. Indeed, her actual risk for having a baby with a chromosomal abnormality is much lower than this. The monosomy 13 and 14 embryos will not be successful at all and the trisomy 14 embryos also have very little chance of surviving much of the first trimester. Most trisomy 13 embryos will also be lost early in first trimester and the few that survive will have only a small chance of surviving the pregnancy and even a smaller chance of living more than a few hours or days after birth. These babies all have severe congenital malformations and if they manage to survive birth and the neonatal period, profound metabolic disturbances, and mental retardation. Indeed, the ‘selective forces’ are so strong against these chromosomally abnormal conceptuses that at least two-thirds of her pregnancies in which a pregnancy is actually confirmed will be chromosomally normal and the chances of actually DELIVERING a chromosomally abnormal baby are probably only about 1%! The overall risk of miscarriage is about 25%. "
so finally, here is our good news: the genetics counselor called me today and told me that she received the blood test results that showed both greg and i have perfectly normal chromosomes! which means, kate does too. the chances of us having another trisomy 13 baby is less than .006%, and kate doesn't have to worry about it either when she's ready to have kids. this is wonderful, wonderful news and an answer to our prayers. when i found out, i literally did a praise-the-Lord happy dance in the middle of a store. and then i privately shed a couple of tears. this is truly the next best thing that could have happened besides jonathan being miraculously healed. i mean, obviously we believe that God is in control and the creator of any future babies we may have. we also know that we can make a beautiful and smart NORMAL baby. but just to know that trisomy 13 probably won't happen again fills me with even more hope for the future of our family.