Cat Cry Syndrome?

[BioABC]

I'm sorry if this is inappropriate, but I was wondering if any of you know what this syndrome is and could give me some details? I did a search but couldnt find anything. Thanks!

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[LifetimeDoc]

Google is your friend...
http://www.medterms.com/script/main/art.asp?articlekey=12062
http://www.answers.com/topic/cri-du-chat-syndrome
http://en.wikipedia.org/wiki/Cri_du_chat

 

[crazy_cavalier]

microdeletion on short arm of chromosome 5, "cri du chat", if I recall correctly from genetics...

 

[SeaBreeze12]

Yup, a deletion in 5p. It's called cry of the cat because infants sounds like mewing cats when they cry.

 

[BioABC]

Thank you to all who responded! Though, I have been unable to find whether it was recessive or dominant.

 

[Haemulon]

I have actually seen this in the lab. Its weird how I would be going through slides and find an abnormality. My reaction was sometimes "Oh cool! Look at this interesting ______ I found!". But then I would think about how it was actually a real patient and would feel so badly for them. The pediatric bone marrows were the worst. But the prenatal stuff was a close second.

 

[SeaBreeze12]

I believe that 90% of the cases are sporadic and has nothing to do with dominate or recessive.

 

[CoolerTHANu]

Thank you to all who responded! Though, I have been unable to find whether it was recessive or dominant.

chromosome deletions aren't really recessive/dominant because they aren't inherited they occur as a de novo error in mitosis or meiosis. but I guess technically its dominant because you only need one chromosome to have the deletion to get the phenotype?

 

[blz]

i remember reading about that syndrome and thinking about The Grudge.

 

[Haemulon]

chromosome deletions aren't really recessive/dominant because they aren't inherited they occur as a de novo error in mitosis or meiosis. but I guess technically its dominant because you only need one chromosome to have the deletion to get the phenotype?

Minor point: chromosome deletions and rearrangements actually can be inherited.

One such case might be the passing on of a chromosome with a translocation that was balanced in the parent's chromosomal constitution (thus little or no phenotypic impact in the parent). If the child recieves only one of the two chromosomes involved, then the condition would not be balanced for them. This effectively creates a deletion condition for the missing part of that chromosome and a trisomic condition for the added portion that was substituted. If both effected chromosomes were passed on (a 1:4 chance in this case), then the child would have inherited the balanced translocation condition of his parent with no detrimental effects.

 

[acedens]

If both effected chromosomes were passed on (a 1:4 chance in this case), then the child would have inherited the balanced translocation condition of his parent with no detrimental effects.

And to be really specific, although there are 4 possible outcomes, the true recurrence risk varies depending on where the translocation is, what chromosomes are affected, how this affects segregation, etc. These vary for every single translocation you find.

Instead of quoting a 1:4 outcome for each possiblility, there are tables in books like Gardner and Sullivan's "Chromosome Abnormalities and Genetic Counseling" that give you specific recurrence risks for several different translocation events. Some of the risks of a liveborn offspring with an aneuploidy would be <2%, because the recombination conditions are typically lethal to cells early in the division process. But others can be as high as 30% or more.

50% would be highest because there is 1 possibility the offspring gets both "typical" chromosomes, 1 possibility they get the balanced rearrangement, then the last 2 possibilities are monosomy/trisomy combinations of the translocation which could lead to an adverse outcome.

Sorry for the rant ... it's just a pet issue.

 

[Haemulon]

And to be really specific, although there are 4 possible outcomes, the true recurrence risk varies depending on where the translocation is, what chromosomes are affected, how this affects segregation, etc. These vary for every single translocation you find.

Instead of quoting a 1:4 outcome for each possiblility, there are tables in books like Gardner and Sullivan's "Chromosome Abnormalities and Genetic Counseling" that give you specific recurrence risks for several different translocation events. Some of the risks of a liveborn offspring with an aneuploidy would be <2%, because the recombination conditions are typically lethal to cells early in the division process. But others can be as high as 30% or more.

50% would be highest because there is 1 possibility the offspring gets both "typical" chromosomes, 1 possibility they get the balanced rearrangement, then the last 2 possibilities are monosomy/trisomy combinations of the translocation which could lead to an adverse outcome.

Sorry for the rant ... it's just a pet issue.

Strong work! You are absolutely right. Thanks for the clarification/elaboration

 

[Critical Mass]

I have actually seen this in the lab.

Are you a cytotech? I read somewhere that you work in a clinical lab, but I didn't know if you were a med tech or what.

Are you going to be working on the side as an M1?

 

[Haemulon]

Are you a cytotech? I read somewhere that you work in a clinical lab, but I didn't know if you were a med tech or what.

Are you going to be working on the side as an M1?

I was a Cytogenetics Tech.. I don't know about working as an M1, because from what I understand it usually takes all of one's time/energy just to keep up with the material. And I really want to focus on slaying that Step I. Maybe there still might be an opportunity to work a little? I'm not counting on it though. When I get started I'll just have to see how things go. I may look into this direction for some research opportunities at least, maybe try to get something published.

 

[Jazz125]

Sorry for the rant ... it's just a pet issue.

No prob! Thanks for the nice description. In a nutshell, its important to do karyotypes on the parents of anyone who's found to have a chromosome abnormality, to see if it's de novo or inherited, as the reproductive implications are very different for each, as acedens so nicely explained!

Too bad they got rid of the genetics forum, eh??

 

[acedens]

Too bad they got rid of the genetics forum, eh??

No kidding! Genetics Forum, you are missed ...

 

[Haemulon]

No kidding! Genetics Forum, you are missed ...

Well, I think a Medical Genetics Residency/Fellowship forum may be in order? A plain old Genetics forum probably not so much (The old one really didn't get much traffic anyway).

 

[evade]

Well, I think a Medical Genetics Residency/Fellowship forum may be in order? A plain old Genetics forum probably not so much (The old one really didn't get much traffic anyway).

I'd join such a forum. I <3 genetics!

Prior to medical school, I worked on the clinical side of medical genetics. Never saw Cri-du-chat, but saw plenty of other crazy stuff!

 

[Jazz125]

I'd join such a forum. I <3 genetics!

Prior to medical school, I worked on the clinical side of medical genetics. Never saw Cri-du-chat, but saw plenty of other crazy stuff!

I haven't really 'seen' a cri-du-chat baby, but i sure heard one once. Another counsellor was taking the family and thh baby to the exam room, and the baby started to cry. It's seriously the eeriest sound you'll ever hear. It really does sound like a cat crying.