Hi, I was recently advised that my 4 year old daughter has an unbalanced chromosomal translocation (long arm y/short arm x). This was discovered after investigations into her global developmental delay. She also has lymphangioma in her eye socket which at this stage is assumed to be unrelated, but who knows. I'm unable to contact the paediatrician at the moment but I have some questions I'd like answered if possible. First of all, I'm a little confused as to why a 'y' chromosome is affected - don't girls only have 'x' chromosomes?? Also, is this likely to affect her menstrual cycle and/or the likeyhood of becoming pregnant when she's older? Soooo confused!! :(
Hello Suz_Mia, First I want appolgize for the length of this response.... But please read the entire response.
I completely undertand your frustration and confusion with respect to your daugthers chromosomal analysis. It is confusing and if you haven't been involved in genetic information before it is definitely overwhelming. I hope I can help to explain somethings, and give you some ideas as to what is happening.
I have some sites I can pass onto you that may help to explain some parts of your questions.
First off, I have a great site that talks about Chromosomal Translocations and the different types of Translocations that can occur. Including a various viable combination of Sex chromosomes chart: http://www.wrongdiagnosis.com/genetics/chromosome.htm
From what I have researched, it sounds like your daughter has a chromosomal arrangement where there is indeed a XY combination. It does talk about how this arrangement is possible due to a "destructed mutation" of the condition called SRY, which is why it is possible for your daughter to be female and not male. .
Read here: (Your daughter falls into category #4)
SRY (for sex-determining region Y) is a gene located on the short (p) arm just outside the pseudoautosomal region. It is the master switch that triggers the events that converts the embryo into a male. Without this gene, you get a female instead.
What is the evidence?
1. On very rare occasions aneuploid humans are born with such karyotypes as XXY, XXXY, and even XXXXY. Despite their extra X chromosomes, all these cases are male.
2. This image (courtesy of Robin Lovell-Badge from Nature 351:117, 1991) shows two mice with an XX karyotype (and thus they should be female). However, as you may be able to see, they have a male phenotype. This is because they are transgenic for SRY. Fertilized XX eggs were injected with DNA carrying the SRY gene.
see Making Transgenic Animals
Although these mice have testes, male sex hormones, and normal mating behavior, they are sterile.
3. Another rarity: XX humans with testicular tissue because a translocation has placed the SRY gene on one of the X chromosomes
4. Still another rarity that demonstrates the case: women with an XY karyotype who, despite their Y chromosome, are female because of a destructive mutation in SRY.
This information is quoted from this site: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/S/SexChromosomes.html
I know this is medical information is difficult and can be hard to digest. My suggestion is, although you will speak to her doctor, I would definitely suggest speaking with a Genetic Counsellor who can really clarify the results of her Karyotype (diagnosis of her genetic structure and chromosomal analysis.) The global delays that you are noticing do tend to come from chromosomal abnormalities. I am not sure if in Australia children and babies get what we call here in Canada and the USA, "Early Intervention". They are available therapies for children who have delays or may have delays due to a range of issues like genetic problems or premature birth. These are best started when a baby is very young (as young as 3 months old) up to around age 6. They have studies that show, the earlier the interventions the better the outcomes with respect to development. It's certainly never too late to start these and I would definitely suggest looking into arranging these for your daughter to assist with her development - either cognitively, physically or both.
I think as well, your suspicions that the eye concern can not be ruled out as related unless a geneticist says they are not. Often times, for example in the Chromosomal Abnormality Trisomy 21 or Down syndrome, there are significant eye problems and situations that are directly related to this chromosomal problem. From lazy eyes, to tear duct issues, to far sightedness and astigmatisms - there are a whole host of eye related issues that are a result of this Genetic problem. And I suspect on a personal level that just like Down syndrome, it doesn't seem far fetched that several other chromosomal problems will have related eye issues. (I know about these because my son has Down syndrome.)
Onto your question regarding whether she will have a menstrual cycle. Here is a sited answer regarding this:
Sometimes the SRY gene is missing from the Y chromosome, or doesn't activate. The fetus grows, is born, and lives as a little girl, and later as a woman, but her chromosomes are XY. Such people are, usually, clearly women to themselves and everyone else. The first premonition that something is wrong may be when menstruation doesn't begin. Occasionally, during meiosis a piece of a Y chromosome transfers to the X, and is carried on into the sperm. Thus the female embryo that results is XX, but develops as a male.
I have also read in a medical journal - (I can not completely or fully access the entire medical journal entry); that due to menstruation problems, either irregular or missing all together is usually the reason why genetic investigations are made and the discovery of the diagnosis of SRY is then obtained. It is very likely that she will have issues surrounding menstruation. If she hasn't menstruated by the time she is 16, doctors say that it should be investigated. I think, if you speak the the genetics specialist or doctors, they will explain why this will be a potential issue. So, I am not sure if knowing this may be a potential problem if she will be able to conceive. If she does have sporadic menses, (unless there is another reason I am unaware of) I can't see why conception would be a problem. But having a translocation genetic issue means that it is possible and likely (I am not sure of the odds, that will have to be assessed by a genetics specialist) she can pass on those genetic issues. (To give you an idea of this: It is the same in Down syndrome which is caused by Translocation, the parent with the Translocation gene will not themselves have the Down syndrome, but they can pass on the translocation which then will result in "Translocation Down syndrome" (one of 3 types of Down syndrome) in the offspring.)
This is probably very hard to digest, and my suggestion is to not base any of your future decisions on what I have written here. You need to consult with primarily a Genetics Doctor and Counsellor. They will better be able to explain and also provide you with the possible scenarios as well as odds for her future children providing that her reproductive systems allow for that.
In addition to anything I have mentioned, please keep in mind, that while I or others may have extensive knowledge in many areas, you should always seek professional medical advice from your own physician, as it pertains to medical conditions or concerns.
Good luck, and if you have any other questions that I can help you with, please feel free to message me directly.
MedHelp Genetics Community Leader;
Down syndrome Community Leader & Ds Group Forum Founder/Moderator
Thank you so much for taking the time to write such an informative response, I really appreciate it.
We're on the waiting list to see a genetic counsellor so I'm looking forward to gaining a little more insight into my daughter's condition. Mia (my daughter) has had several health issues and at the very least it would be good to finally know what's causing them.
My understanding is that she has an xy translocation, with partial deletions at the breakpoint on the x chromosome. This has been very confusing for me but at least I feel we are finally getting some answers. Since Mia was 6 months old we have been regulars at the hospital, for several issues including her orbital lymphangioma (a rare benign tumor) which has caused significant vision-loss in one eye, some hearing issues which are still being investigated, and of course her developmental and growth delays - her speech & language is on the 1st percentile, she has several 'autistic-like' characteristics, echolia, her height & weight is below the 3rd percentile and head size is below the 2nd percentile.
When I find out anything new I will post it here :)
You are very welcome, and I look forward to hearing what you learn from the Genetics Doctors appointment. I know that things do seem a bit overwhelming, but keep persevering. If ever you need to just chat, please do let me know! I am always available.
Let me know when you get more information!
MedHelp Children - Special Needs Community Leader; Genetics Community Leader;
Down syndrome Community Leader & Ds Group Forum Founder/Moderator
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