Questions for answers . . .

A

anonymous

New member
I am currently looking for information for a book that I am researching. A child in this finctional story is born with CF and I would be very much indebted if I could have a few questions answered about it.

He has both a younger brother and sister (twins) and if anyone could tell me the likelyhood that they might have the same condition it would really help me.

I was also wondering if perhaps anyone would know if just one parent could be the carrier rather than both as I would like to isolte this in the series that is being written.

Any help would, again, be great appriciated and I cannot thank anyone enough as you can never find information that is as good as from the people who know it best.
 
A

anonymous

New member
I am currently looking for information for a book that I am researching. A child in this finctional story is born with CF and I would be very much indebted if I could have a few questions answered about it.

He has both a younger brother and sister (twins) and if anyone could tell me the likelyhood that they might have the same condition it would really help me.

I was also wondering if perhaps anyone would know if just one parent could be the carrier rather than both as I would like to isolte this in the series that is being written.

Any help would, again, be great appriciated and I cannot thank anyone enough as you can never find information that is as good as from the people who know it best.
 
A

Allie

New member
1st question: The chaces are 1 in 4 of having a Cf child, so it's possible, yes.

2nd question: No, they both have to be carriers for the child to have the disease.

Best of luck!
 
A

Allie

New member
1st question: The chaces are 1 in 4 of having a Cf child, so it's possible, yes.

2nd question: No, they both have to be carriers for the child to have the disease.

Best of luck!
 
J

JazzysMom

New member
OK now I have a ??? on this. Is the 1 out of 4 for identical twins only or fraternal twins since fraternal come from 2 different eggs? (if I am correct in my explanation). Since each pregnancy the odds are the same, I wonder what happens with multi babies?!
 
J

JazzysMom

New member
OK now I have a ??? on this. Is the 1 out of 4 for identical twins only or fraternal twins since fraternal come from 2 different eggs? (if I am correct in my explanation). Since each pregnancy the odds are the same, I wonder what happens with multi babies?!
 
A

Allie

New member
If they are identical, they will either both have it or both not. But seeing as they are boy-girl twins, the chances are equal because they cannot be identical.
 
A

Allie

New member
If they are identical, they will either both have it or both not. But seeing as they are boy-girl twins, the chances are equal because they cannot be identical.
 
J

JazzysMom

New member
They cant be identical?! WHY? ONLY KIDDING....thats for clarifying it Allie! Each pregnancy is 1 out of 4 which is where I was confusing it. Not each baby!
 
J

JazzysMom

New member
They cant be identical?! WHY? ONLY KIDDING....thats for clarifying it Allie! Each pregnancy is 1 out of 4 which is where I was confusing it. Not each baby!
 
M

miesl

New member
Re: twins.

Identical twins (or higher order multiple). Since they have the same genetic makeup - it's the same odds as a single birth - one in four (the twins will either both have CF (25%), both be carriers (of the same gene - 50%), or both carry no CF gene at all (25%))

Non-identical twins (or higher order multiple). These do not share the same genetic makeup. Each child must be considered separately. There are 16 possible outcomes.

1 in 16 that both will have CF
1 in 16 that both will carry no CF gene
1 in 8 (2 in 16) that one will have CF and the other will carry no CF gene.
1 in 4 (4 in 16) that both will be carriers
1 in 4 (4 in 16) that one will be a carrier and the other will have CF
1 in 4 (4 in 16) that one will be a carrier and the other will carry no CF gene.
 
M

miesl

New member
Re: twins.

Identical twins (or higher order multiple). Since they have the same genetic makeup - it's the same odds as a single birth - one in four (the twins will either both have CF (25%), both be carriers (of the same gene - 50%), or both carry no CF gene at all (25%))

Non-identical twins (or higher order multiple). These do not share the same genetic makeup. Each child must be considered separately. There are 16 possible outcomes.

1 in 16 that both will have CF
1 in 16 that both will carry no CF gene
1 in 8 (2 in 16) that one will have CF and the other will carry no CF gene.
1 in 4 (4 in 16) that both will be carriers
1 in 4 (4 in 16) that one will be a carrier and the other will have CF
1 in 4 (4 in 16) that one will be a carrier and the other will carry no CF gene.
 
H

HD

New member
wow the math is mind boggling!

Right before my guy went in for his G tube I was trying to relax and read some literary prozac. So I'm reading this myster/romance and the hero guy was sad and no one knew why. Well it turns out the guy's daughter died of CF. grrrrrr! Should have had a warning label! lol
 
H

HD

New member
wow the math is mind boggling!

Right before my guy went in for his G tube I was trying to relax and read some literary prozac. So I'm reading this myster/romance and the hero guy was sad and no one knew why. Well it turns out the guy's daughter died of CF. grrrrrr! Should have had a warning label! lol
 
J

julie

New member
I have a website on CF and male infertility which is somewhat irrelevant to your questions but it does have a user-friendly table of probabilities for inheriting CF based off of the carrier status of the parents (i.e. one parent is a carrier, one parent HAS CF). You can see it at <a target=new class=ftalternatingbarlinklarge href="http://www.cysticfibrosismaleinfertility.com/Where_to_begin.html">http://www.cysticfibrosismaleinfertility.com/Where_to_begin.html</a>, scroll down just a tad and you should see it.

The probability is really a stab in the dark though, in the family you described, there are some similar sized families here on this site. Sometimes All the children will have CF, sometimes only one child, sometimes two will have CF and the others will not. As others have stated, if the twins are identical they will either BOTH have CF or both NOT have CF. If they are fraternal, the probabilities return to the same ratio, although it is medically rare for BOTH twins (fraternal) to have CF. I think there are two or three sets of fraternal twins on this site that both have CF.

Your second question poses a complicated answer. As Allie and some others answered, NO, BOTH parents must be carriers to have a child with CF. This is the case in 99.9999999999999% of all CF cases.

Although, there ARE a limited number of cases where gene transfer from mom and gene transfer from dad to baby in utero did not occur as it should have. There is ONE family on this site where mom is NOT a carrier at all, child with CF IS biologically her and her husbands child (DNA testing was done) and initially her husband was diagnosed as a carrier. When baby was Dx with CF they were in absolute shock. Come to find out, dad carried 1 common and 1 very rare mutation that was found after extensive testing. In the genetic transfer in Utero, baby got BOTH of DAD's Chromosome 7's instead of 1 from mom and 1 from dad. Resulting in a child with CF from the most unique situation possible. I'm sure this is much more than you were looking for, for the purposes of your book but just in case you (or anyone else) ever heard of soemthing different, I wanted to lay that information out there.

If you have more questions, I/we are happy to help you out.
<a target=new class=ftalternatingbarlinklarge href="mailto:division902@hotmail.com">division902@hotmail.com</a>
 
J

julie

New member
I have a website on CF and male infertility which is somewhat irrelevant to your questions but it does have a user-friendly table of probabilities for inheriting CF based off of the carrier status of the parents (i.e. one parent is a carrier, one parent HAS CF). You can see it at <a target=new class=ftalternatingbarlinklarge href="http://www.cysticfibrosismaleinfertility.com/Where_to_begin.html">http://www.cysticfibrosismaleinfertility.com/Where_to_begin.html</a>, scroll down just a tad and you should see it.

The probability is really a stab in the dark though, in the family you described, there are some similar sized families here on this site. Sometimes All the children will have CF, sometimes only one child, sometimes two will have CF and the others will not. As others have stated, if the twins are identical they will either BOTH have CF or both NOT have CF. If they are fraternal, the probabilities return to the same ratio, although it is medically rare for BOTH twins (fraternal) to have CF. I think there are two or three sets of fraternal twins on this site that both have CF.

Your second question poses a complicated answer. As Allie and some others answered, NO, BOTH parents must be carriers to have a child with CF. This is the case in 99.9999999999999% of all CF cases.

Although, there ARE a limited number of cases where gene transfer from mom and gene transfer from dad to baby in utero did not occur as it should have. There is ONE family on this site where mom is NOT a carrier at all, child with CF IS biologically her and her husbands child (DNA testing was done) and initially her husband was diagnosed as a carrier. When baby was Dx with CF they were in absolute shock. Come to find out, dad carried 1 common and 1 very rare mutation that was found after extensive testing. In the genetic transfer in Utero, baby got BOTH of DAD's Chromosome 7's instead of 1 from mom and 1 from dad. Resulting in a child with CF from the most unique situation possible. I'm sure this is much more than you were looking for, for the purposes of your book but just in case you (or anyone else) ever heard of soemthing different, I wanted to lay that information out there.

If you have more questions, I/we are happy to help you out.
<a target=new class=ftalternatingbarlinklarge href="mailto:division902@hotmail.com">division902@hotmail.com</a>
 
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