1P36 stuff

Hey all,

we have yet to post a full history for Zoe, but that is a major project so we are taking it one piece at a time. Today's piece- what is 1P36? There is a Wikapedia site that covers most everything, and has a very cute picture of who I think is a young Whitney (Nate and Melanie's little girl- there is a link to her blog on the right there). It's pretty good- some of the info may have changed a bit though. Anyway, just FYI here's our take on 1P36 and Zoe in particular.

1P36 is a chromosomal deletion syndrome where a small piece of the end (the terminal end) of the short arm (the p arm) of chromosome 1 is missing. It is classed in a couple of different ways- the very specific where they count the missing base pairs of DNA segments (we don't know this for Zoe) and the not so specific where they identify the general segment of the 1P36 p arm where the break point occurs. The is generally classed as 1P36.1 (the largest deletion), 1P36.2 and 1P36.3 (the smallest amount of missing material).

So I was going to go through a list of the characteristics of 1P36 kids, but I'll direct you to the Wikapedia site instead. Here it is- http://en.wikipedia.org/wiki/1p36_deletion_syndrome

On to Zoe. Zoe has 1P36.1, the largest type of deletion. Her's occurred as a result of an unbalanced translocation of chromosomes at the time of meiosis (creation) of the egg or sperm- whether this was maternally derived or paternally we don't know. What happened is a piece of one of her 13 chromosome (I'm going to presume you all kind of understand genetics and how there are generally 23 pairs of chromosomes) jumped onto the end of one of her 1 chromosomes. This kind of translocation can occur in anyone, as long as nothing is lost (balanced translocation) there are no ill effects for that individual (though it can cause problems if they go on to have kids of there own). So Zoe, technically, has only 35 chromosomes, as one of her 13's is joined on her 1. When the 13 piece jumped, it knocked off pieces of the 1P36 and the entire 13p (small arm of 13) chromosome, so technically she has 2 chromosome deletions. We were told that the 13p segment was insignificant genetically speaking (though I have since learned that some 13q deletions are not such good news, so we got lucky there). Her deletions are classed as "de novo" meaning just by chance, or, in other words, she just lost the genetic lottery that causes 1P36 in an estimated 1 in every 5000-10000 births(surprisingly common, actually- it's thought to be the most common chromosomal deletion syndrome).

With Zoe, the clinical manifestations of 1P36 show up in a variety of areas. I'll break it down for you into systems.

Cardiac

Zoe has or has had a number of heart defects present from birth/soon after birth- an atrial septal defect (ASD), a ventricular septal defect (VSD), a patent ductus arterious (PDA), a weird ass tricuspid valve (yes, weird ass is a medical term), Left ventricle non-compaction cardiomyopothy (LVNC) and hypertrophy of the right atrium (as a possible compensation for the LVNC?). Most of these things have healed up on their own and don't show up on her echocardiograms (ultrasound of the heart) anymore, leaving her with the funky valve, slight hypertrophy (thickening of the heart wall), and moderate LVNC. The most worrying thing is the LVNC- it is a condition where the muscle wall of the left ventricle doesn't form properly in utero- it has a spongy (i.e. non compacted) appearance and can't push the blood around her body as well as it should. It's a rare cardiomyopothy, though we have now found 4 other 1P36 families whose kids have it, thus suggesting a correlation. Her ejection ratio (ER)- the percentage of blood in the ventricle that gets ejected per heart beat- is currently around 40%. The norm is around 65%. She takes Captopril, an ACE inhibitor, to lower the blood pressure in the major vessels around her heart, thus making the heart work less hard (terrible grammar there, but too bad). This is good because if the heart works too hard the tissue becomes fibrous, and if that happens too much the heart fails. This is not a definite thing, but if it does happen Zoe will need a heart transplant. Some people this never occurs, and they die at 95. Some, well, it does.

Communication/speech/hearing/vision

Like all kids with 1P36, Zoe has a profound speech delay. She has not developed the typical pre-verbal behaviours like typical cooing, consonant sounds, babbling, etc. Zoe is typically a very quiet little girl. Time will tell how much speech she develops. She is learning sign language though- 3 signs and counting!

Hearing- Zoe is somewhat hearing impaired, though to what functional extent we don't know yet. We see audiology every 3 months or so.

Vision- Zoe is quite far sighted (meaning seeing things close to her is tricky). She wears glasses as often as possible that have a pretty significant prescription in them. We have seen significant gains in her tracking and focusing in last couple of months- glasses on and off.

Development- Cognitive/Emotional/Social/physical

Zoe is learning new stuff every day, but it takes her a long time to learn things. Rolling took over a year, as did using a cup. Her eating has always been amazing, though slow and an enormous time commitment for us all. Breast feeding was a huge effort for her and Genevieve, and I am so proud of both of them for doing it because we feel it had a huge impact on how well Zoe is doing now. She is learning to sit unsupported for a few seconds at a time (up to 20 so far, and much longer with minimal support) and developing her standing muscles. We don't expect immediate breakthroughs, but we have seen some great progress in just the last week or so. Just like everything else with Zoe though, it takes time, and a lot of effort on her part (and ours).


1P36 features

Zoe was born with a number of the typical characteristics of 1p36. These include noticeable things noted in the literature like flat nasal bridge, wide spread eyes, pointed chin, small mouth etc and other stuff like microcephaly, large fontanels (soft spot on the skull- all babies have them), a sacral dimple (non communicative) etc etc. She also shares a lot of features that we've only seen by talking with other 1P parents- she doesn't produce tears, for instance and she is extremely fuzzy, like a lot of 1P 36 kids. When the kids get together you can really see what the geneticists talk about when they look for the characteristic dysmorphic features of 1P36- all the kids look like cousins- similar yet different. Very similar. And all very beautiful.

Anyway, I can't think of anything else to say about Zoe and her 1P36 stuff. I'm off to make dinner. Hope this has been a useful primer. Next up- Zoe's history!