HELP: Chromosomal Insertion of X Chromosome in Male fetus

[smartins]

Hello,

My family member is 20 weeks pregnant and has recently had an amniocentesis done to see if the fetus has any chromosomal abnormalities, as she herself has a pericentric inversion of the X chromosome. She is (46,X,inv (X) (p11.23q21.2)). She was told that she'd likely have a female child as inheritance in a male would be fatal and besides having difficulty becoming pregnant the likelihood of having issues in the offspring was low. However, after the amniocentesis, it has been discovered that it is indeed a male fetus that has an insertion instead of the expected inversion and is, 46,Y,ins(x)(p22.1q13q22). She is having difficulty gathering reliable and common information from the physicians she is dealing with and is desperate for more information. If anyone knows anything about these abnormalities, PLEASE help. We are running out of time

[Psycho]

The problem is so specific no one is going to be able to give you an answer here, the physician isn't being evasive, it is the fact that there isn't any common information relating to it and therefore the little information available maybe unreliable or irrelevant.

 

There is this website that maybe able to help but I couldn't find anything specifically relevant to that abnormality.

 

Link

[smartins]

The problem is so specific no one is going to be able to give you an answer here, the physician isn't being evasive, it is the fact that there isn't any common information relating to it and therefore the little information available maybe unreliable or irrelevant.

 

There is this website that maybe able to help but I couldn't find anything specifically relevant to that abnormality.

 

Link

 

Thank you for the reply.

 

I understand how exceptionally rare this particularly chromosomal abnormality is. They are performing a SNP array analysis to detect unbalances (deletions or duplications) not detected by the amnio. My understanding is that if this is a "balanced" insertion then that is much more favorable to an unbalanced insertion.

 

For instance, I read this on one website:

"If someone carries a balanced insertional rearrangement, they should not have any symptoms (unless a critical gene is disrupted at the breakpoints) but they are at risk of producing a child with either a deletion or a duplication of chromosomal material but not both disorders."

 

Would this appear to be accurate?

[Psycho]

Thank you for the reply.

 

I understand how exceptionally rare this particularly chromosomal abnormality is. They are performing a SNP array analysis to detect unbalances (deletions or duplications) not detected by the amnio. My understanding is that if this is a "balanced" insertion then that is much more favorable to an unbalanced insertion.

 

For instance, I read this on one website:

"If someone carries a balanced insertional rearrangement, they should not have any symptoms (unless a critical gene is disrupted at the breakpoints) but they are at risk of producing a child with either a deletion or a duplication of chromosomal material but not both disorders."

 

Would this appear to be accurate?

A balanced insertional rearrangement is where two breaks occur in two different chromosomes and they swap the two pieces around. If this has been successful no DNA will be lost.

 

So that statement is accurate. Primarily all the information is there it just hasn't been filed properly, this can cause problems in reproduction later in life.

 

In an unbalanced rearrangement this means that 2 bits have swapped over and been put back in the wrong place but some of one or both the bits has been lost or doubled up on the way, this means that some genes maybe expressed at the twice the level they should (in duplication) or not at all (in deletion) however deletion or duplication could also be asymptomatic if it is in an intronic region (region not used by the DNA) however this is less likely.

Edited November 6, 2011 by Psycho