Re: Triploidy

[p2b]

Hi
My husband and I went to our consultant follow up appointment this morning after my MMC two months ago. We found out our baby was a girl and the autopsy points to a chromosonal abnormality called Triploidy where three sets of chromosones are present instead of the 2 that should be there. The pathologist is fairly confident that this extra set were from the maternal side. The consultant was thorough going through the report and said that any further pregnancies would probably be classed as high risk and we would be talked through the chromosonal tests available. It was at this point that I told him I was already pregnant. I have done a bit of research and it appears that the likelihood of this abnormality recurring is no higher for me than for the general population so I'm hoping the consultant care is an acknowledgement of what has happened rather than something to get really worried about. Does anyone have any experience of Triploidy? I'd be very grateful to hear your experiences.

p2b

[Blandmum]

I can't give you any direct advice, there are genetics experts on MN who will be able to give you more information on this (Tamum for one), but I didn't want your post to be unanswered.

Triploidy happens whenthere is a problem in the production of one of the sex cells. Normallt when they are made the number of chromosomes in the cell is halved. So instead of 46 chromosomes you should only have 23 in an egg or a sperm.

Sometimes the cell division doesn't work properly, and all the chromosomes end up in one cell, instead of dividing up between two cells.

Sorry if this is going over old ground for you, and hope that one of our resident experts comes along soon.

[majormoo]

Hi I am sorry about your miscarriage. I do not have experience of Triplody but wanted to reply as I saw no one with specific knowledge had replied yet.
I had a termination a couple of years ago, as my baby had Trisomy 13, another chromosonal abnormality. We were given an automatic recurrence risk of 1 in 100 in future pregnancies, but were told that the real risk for us was probably far smaller than that. This is because of the karotyping that was done following our CVS (I get a bit confused here so am afraid cannot elaborate further on what that means but you may well know about the karotyping anyway) I wanted to let you know that I had a healthy son a year ago.

I wish you well with your new pregnancy. I know how hard it is, worrying that the problem will recur.

[ADDICTEDtosayingHAAAAAAAPYxmas]

Can someone explain to me about triploidy. do both parents have to be a carrier or only one parent?

[p2b]

Hi

I have taken this from a website to try and explain Triploidy.

"Triploidy arises when three sets of 23 chromosomes combine to form the embryo. This is a random occurrence which is not known to be related to anything either parent may or may not have done. It arises either when two sperm fertilize one egg or when two cells fail to separate in the formation of the egg resulting in an egg with 46 chromosomes being fertilized by one sperm".

The important thing to note in the above definition is that the condition is generally considered to be a random occurence. My previous pregnancy was triploidy and I am now pregnant again and being scanned regularly by a consultant. He has told me that there is zero chance of reoccurence. This is because there are no carriers of triploidy - its either a problem with the way in which the egg splits at the beginning or the fact that two sperm (which shouldn't normally happen) fertilize the same egg. Obviously there are cases of reoccurence but my consultant has tried to reassure me that these are very very rare and again this is a random occurence.

I hope this helps - please let me know if I can help further. I am off for another scan on Thursday when i will be 12.5 wks. I am trying very hard to remember what the consultant has said - hopefully this time all will be well.

p2b

[ADDICTEDtosayingHAAAAAAAPYxmas]

oh cos my friend has been told her dad and brother are carriers of it. she is pregnant so they are trying to find out if she is a carrier aswell and to work out the risk of this baby being born with trisomy whatever. i think its 13 and 14 that her family are carriers of.

[Tamum]

You can't possibly be a carrier of triploidy- p2b is right, it's a random occurrence (sorry I didn't see this thread the first time, p2b). I think, Addicted, you are muddling up trisomy (an extra chromosome- you can be a carrier of this if you have a translocation) with triplody (an entire extra set of chromosomes).

Good luck with your next scan, p2b.

[Millarkie]

It sounds more likely that they are carriers of a translocation between chromosomes 13 and 14 - that would make them at risk of trisomy 13 and trisomy 14 pregnancies.
If this is the case it is because two chromosomes are 'stuck together' in the 'carriers', this disrupts the division of the chromosomes when the eggs/sperm are being formed so sometimes there is an imbalance with an egg/sperm carrying an extra copy of one of the chromosomes.

[ADDICTEDtosayingHAAAAAAAPYxmas]

oh ok my friend said it was called triploidy but she must have been wrong.