Re: Re: geneticsresponse/reply

[Guest guest]

You got it!

n Rojas

[Guest guest]

I didn't know it was possible to " Carry " 2 CF genes in the same person. Is

this what you " re saying here? Does anyone know of this situation? I thought

CF genes were found on chromosome 7. Does this mean two " bad " genes are on

the same chromosome? Enlighten me, please.

[Guest guest]

Hi all,

Sorry to prolong the agony, but from what I understand

reading this thread, there is no argument that it

takes two carriers to make a cf child - that's a

given.

I believe the argument is whether it REQUIRES two

carriers to produce a mere carrier.

Because my poor feeble brain requires pictures to

get the idea, all the pretty charts in every CF

book I've read so far has indicated that a single

defective cf gene can be passed on to a child from

a single cf carrier, thereby making the child a

cf carrier, and does not require the other parent

to be a carrier too. However, in the case where

there is a single carrier, you COULD NOT have a

child with the full-blown disease. It simply doesn't

preclude them from being carriers themselves.

Also, if someone has more than one defective cf

gene, they would not be a cf carrier, they would

have the full-blown disease, since the genes come in

pairs - like shoes! ;-)

Have I got the gist of this thread correct?

hugs,

mommy to and , both wcf and

obviously a carrier herself, along with her DH

> So carrier status can be passed from a single parent

> who is a

> carrier, and it does take two carriers (with one or

> more defective cf

> gene) to produce a child with cf, and two carriers

> CAN produce a

> child who does not carry any copies of the defective

> gene.

>

> I did enjoy the shoe analogy!

>

>

> ~

> mommy of 3, 1 wcf

>

>

__________________________________________________

[Guest guest]

Chromosome y carries the " genes. " One in herits, to be precise, one alelle

from

each parent; they may differ; we just saw a post about a person with one R117H

and one DeltaF508; it talkes two to produce cf; only one makes one a carrier.

I hope this helps,

n Rojas

[Guest guest]

<< However, in the case where

there is a single carrier, you COULD NOT have a

child with the full-blown disease. >>

Of course, this is difficult to impossible to be SURE that you are NOT a

carrier, since the current test only tests for some 90 mutations, out of more

than 800 known mutations.

Jen, who is surely adding confusion to a thread which I am coming in on the

tail end of...haven't even read the other emails, lol......

[Guest guest]

<< Also, if someone has more than one defective cf

gene, they would not be a cf carrier, they would

have the full-blown disease, since the genes come in

pairs - like shoes! ;-)

>>

and to further complicate matters......

they would have the full blown disease......UNLESS they happened to inherit

two of the more rare mutations that do not always CAUSE the full blown

disease (as in the case of the folks without the diagnosis of CF but with

congentital absence of vas deferans......) (CAVD?)

Jen, who has no idea why she is trying to confuse people tonight......

[Guest guest]

<< I didn't know it was possible to " Carry " 2 CF genes in the same person.

Is

this what you " re saying here? Does anyone know of this situation? I thought

CF genes were found on chromosome 7. Does this mean two " bad " genes are on

the same chromosome? Enlighten me, please.

>>

OK, getting into the conversation rather late......we carry all the genes

that we carry, so I imagine that it was a matter of mere semantics.......

if you have two copies of the CF mutations, and hence CF (or congental

absence of vas deferans....), then you could either say you carry two

mutations, or you could say you inherited two copies of the mutation.

Whoever said that if you carry two copies of the gene was probably trying to

explain that the odds go up for the kids to have CF or to be carriers if the

parent has more than one copy. In our case, with two carrier parents (mine),

in other words, then my sisters and I could all be carriers of one mutation

or another, or could have ended up with two copies. In the case of all of

our kids on the list, two parents being carriers lead to a 1 in 4 chance of

inheriting two copies of the CF mutation. If there are folks /parents on the

list who also have CF,then the odds would be higher than one in four, if they

happened to marry a carrier. If they married a person with CF, so both

parents have CF, then obviously all the kiddos would have CF, because there

would be no " non-defective " copies to inherit.

Jen

[Guest guest]

Yup; you got it!

n Rojas who both as a person with cf and a parent of a cf child

definitely gets

it! But there is always the Human Genome projerct or a recent college text

in gene

tics; I'm not the final word!

n Rojas

[Guest guest]

The gene cannot be from the y chromosome. This is the chromosome that

determines sex (male). If this were true, then females would never have CF, nor

carry it.

Re: Re: geneticsresponse/reply

Chromosome y carries the " genes. " One in herits, to be precise, one alelle

from

each parent; they may differ; we just saw a post about a person with one R117H

and one DeltaF508; it talkes two to produce cf; only one makes one a carrier.

I hope this helps,

n Rojas

[Guest guest]

yep. in the case of a CFer, they have two CF genes. Whatever mutations is more

dominant will have the most effect. i do not know if the more effective

mutations mute the weaker or if they blend in their effects, but yes, CFers have

TWO CF genes, each located on homologous chromosomes.

Re: Re: geneticsresponse/reply

<< I didn't know it was possible to " Carry " 2 CF genes in the same person.

Is

this what you " re saying here? Does anyone know of this situation? I thought

CF genes were found on chromosome 7. Does this mean two " bad " genes are on

the same chromosome? Enlighten me, please.

>>

OK, getting into the conversation rather late......we carry all the genes

that we carry, so I imagine that it was a matter of mere semantics.......

if you have two copies of the CF mutations, and hence CF (or congental

absence of vas deferans....), then you could either say you carry two

mutations, or you could say you inherited two copies of the mutation.

Whoever said that if you carry two copies of the gene was probably trying to

explain that the odds go up for the kids to have CF or to be carriers if the

parent has more than one copy. In our case, with two carrier parents (mine),

in other words, then my sisters and I could all be carriers of one mutation

or another, or could have ended up with two copies. In the case of all of

our kids on the list, two parents being carriers lead to a 1 in 4 chance of

inheriting two copies of the CF mutation. If there are folks /parents on the

list who also have CF,then the odds would be higher than one in four, if they

happened to marry a carrier. If they married a person with CF, so both

parents have CF, then obviously all the kiddos would have CF, because there

would be no " non-defective " copies to inherit.

Jen

***********************

This is a secular list.

***********************

PLEASE do not post religious emails to the list.

--------------------------------------------------

The opinions and information exchanged on this list should

IN NO WAY

be construed as medical advice.

PLEASE CONSULT YOUR PHYSICIAN BEFORE CHANGING ANY MEDICATIONS OR TREATMENTS.

--------------------------------------------------

Our webpage is at http://www.eohio.net/malbright/cfparents.htm

_________________________________________________

Post message: cfparentsegroups

Subscribe: cfparents-subscribeegroups

Unsubscribe: cfparents-unsubscribeegroups

List owner: cfparents-owneregroups

_________________________________________________

WE HAVE A CHAT PAGE!!!

/chat/cfparents

_________________________________________________

[Guest guest]

No, my question is, can a person carry two CF genes ON THE SAME CHROMOSOME

with a NORMAL " other " chromosome? I think this was what someone was saying

earlier.

[Guest guest]

Once again, my question (and it appears that I'm not being clear) is: Can a

CARRIER (like me) " carry " two CF genes -- like Delta F508 + another -- on the

same chromosome, with the other chromosome totally normal, and thus just be a

carrier? I KNOW that CF patients " carry " 2 CF genes, but ONE is on

Chromosome 7 from Mom and one is on Chromosome 7 from Dad. Is it possible

that someone has 2 different genes on the same Chromosome?

[Guest guest]

I believe you are right and it is chromosome 7. we have been talking to a

genetic counselor about finding out our mutations and I think that is what

she said also.

Lori

Re: Re: geneticsresponse/reply

>

>

> Chromosome y carries the " genes. " One in herits, to be precise, one

alelle

> from

> each parent; they may differ; we just saw a post about a person with one

R117H

> and one DeltaF508; it talkes two to produce cf; only one makes one a

carrier.

> I hope this helps,

> n Rojas

>

>

>

[Guest guest]

In general I think most Dr.s believe that the " least defective " mutation

will rule, but I don't know that any definitive research has been done on

this. It does give us hope though that only giving partial function might be

enough to make a huge difference in life expectancy.

Lori

Re: Re: geneticsresponse/reply

> yep. in the case of a CFer, they have two CF genes. Whatever mutations

is more dominant will have the most effect. i do not know if the more

effective mutations mute the weaker or if they blend in their effects, but

yes, CFers have TWO CF genes, each located on homologous chromosomes.

[Guest guest]

At the risk of continuing down the abyss, each child receives one chromosome

7 from Mom and one chromosome 7 from Dad. Thus, I do not believe they check

to see if they carry the chromosome, since they will have two of them.

[Guest guest]

I've never studied that, but it would seem logical to me that a carrier can

carry only one mutation, even in the same chromosome.

n.. the genetic wiz.... what do you think of it ? ;-)

-----Message d'origine-----

De : jfkdc@...

Envoyé : mardi, 16. janvier 2001 12:18

À : cfparentsegroups

Objet : Re: Re: geneticsresponse/reply

Once again, my question (and it appears that I'm not being clear) is: Can a

CARRIER (like me) " carry " two CF genes -- like Delta F508 + another -- on

the

same chromosome, with the other chromosome totally normal, and thus just be

a

carrier? I KNOW that CF patients " carry " 2 CF genes, but ONE is on

Chromosome 7 from Mom and one is on Chromosome 7 from Dad. Is it possible

that someone has 2 different genes on the same Chromosome?

***********************

This is a secular list.

***********************

PLEASE do not post religious emails to the list.

--------------------------------------------------

The opinions and information exchanged on this list should

IN NO WAY

be construed as medical advice.

PLEASE CONSULT YOUR PHYSICIAN BEFORE CHANGING ANY MEDICATIONS OR TREATMENTS.

--------------------------------------------------

Our webpage is at http://www.eohio.net/malbright/cfparents.htm

_________________________________________________

Post message: cfparentsegroups

Subscribe: cfparents-subscribeegroups

Unsubscribe: cfparents-unsubscribeegroups

List owner: cfparents-owneregroups

_________________________________________________

WE HAVE A CHAT PAGE!!!

/chat/cfparents

_________________________________________________

[Guest guest]

I am going to hazard a guess and say no you can't. Here is my reasoning. I

know that if they are checking for CF during prenatal diagnosis and don't

know what say the father's mutation is, they will go on to check to see if

the baby inherited that chromosome from the father. If the baby didn't then

they would say no CF.

This is really beyond my knowledge area, so there are quite possibly huge

holes in my theory. If we don't have a good answer by Friday; I will be

happy to ask a genetic counselor how that all works.

Lori

Re: Re: geneticsresponse/reply

> No, my question is, can a person carry two CF genes ON THE SAME CHROMOSOME

> with a NORMAL " other " chromosome? I think this was what someone was

saying

> earlier.

>

> ***********************

> This is a secular list.

> ***********************

>

>

> PLEASE do not post religious emails to the list.

>

>

> --------------------------------------------------

>

>

> The opinions and information exchanged on this list should

> IN NO WAY

> be construed as medical advice.

>

> PLEASE CONSULT YOUR PHYSICIAN BEFORE CHANGING ANY MEDICATIONS OR

TREATMENTS.

>

> --------------------------------------------------

>

>

> Our webpage is at http://www.eohio.net/malbright/cfparents.htm

>

> _________________________________________________

> Post message: cfparentsegroups

> Subscribe: cfparents-subscribeegroups

> Unsubscribe: cfparents-unsubscribeegroups

> List owner: cfparents-owneregroups

> _________________________________________________

>

> WE HAVE A CHAT PAGE!!!

> /chat/cfparents

> _________________________________________________

>

>

>

[Guest guest]

<< Once again, my question (and it appears that I'm not being clear) is: Can

a

CARRIER (like me) " carry " two CF genes -- like Delta F508 + another -- on the

same chromosome, with the other chromosome totally normal, and thus just be a

carrier? I KNOW that CF patients " carry " 2 CF genes, but ONE is on

Chromosome 7 from Mom and one is on Chromosome 7 from Dad. Is it possible

that someone has 2 different genes on the same Chromosome?

>>

I truly don't know....but I guess I can ask ron, he is the one with the

stupid PHD in genetics.....

the only thing that I do recall related to this is that someonen posted

awhile back, like more than a year, that one of their children has 3 copies

of the CF mutated genes? I think this might have been on conncoll????? I

had never heard of this before....but the parent said this was determined to

be the case (I th ink I recall that one parent at least had CF....) again,

thats the only time I ever heard that mentioned. Then at Disney, we happened

to meet a doctor in line who did research with the doc who discovered the

gene. We got to talking about Mallory...and about our family's weird

genetics,and she actually asked me if it were possible that Mallory had

picked up three copies rather than 2 of the mutations????? so, the second

time I have heard this mentioned. Have no idea how true this can be, though,

and have not even considered it any further. I have her email addy, perhaps

I will ask her sometime.

Anyway, so if you find the answer you seek, I would like to hear the answer.

Anyone on conncoll remember the family I mention????

Jen

[Guest guest]

<< I was always told that two mutations

= CF. However, this would help explain why both

babies have CF - their chances of having the disease

was raised from 25% to 50% if he was carrying two

mutations instead of one. >>

UM....., wouldn't this actually raise their chances to 75%????? At

least, that is how I think it works....

have you guys had genetics testing? at least the genzyme test that tests for

about 90 mutations?????

VERY interesting that your hubby has CAVD..... did you guys do in vitro?

Jen

[Guest guest]

Jen,

Thank you, this is absolutely true. What I meant was

that despite the fact that we can't test for all

mutations, if a person is not a carrier (whether we

can test for it or not) they could not produce a

child with the full blown disease. Of course we

wouldn't know they weren't carriers for sure, even

if they had dozens of children and none of them had

CF.

C.

mommy of and , both wcf

--- ron88jen@... wrote:

>

> In a message dated 1/16/01 5:27:03 AM,

> pswyd@... writes:

>

> << However, in the case where

> there is a single carrier, you COULD NOT have a

> child with the full-blown disease. >>

>

> Of course, this is difficult to impossible to be

> SURE that you are NOT a

> carrier, since the current test only tests for some

> 90 mutations, out of more

> than 800 known mutations.

>

> Jen, who is surely adding confusion to a thread

> which I am coming in on the

> tail end of...haven't even read the other emails,

> lol......

>

__________________________________________________

[Guest guest]

Jen; thank you for your kind post earlier. With regard to genetics, I'd say

" ask Ron. "

This has been an on going issue on cfparents for heaven knows how long when I

attempted a simple (and accurate) answer to a question from a parent who had

thought that a patient could acquire CF from only one parent (rare, but

unlikely)

and I did an enormous amount of research to support what I already knew and

posted it, and as a result am being " challenged " by I forget who to " prove "

that

one pareent with one gene copy (whether identical or not) can marry a non

carrier

and have a one in two chance of producing a cf child! (yet!) Get Ron on

line; I am

tired, with my stupid Ph.D's in clinical psychology and neuropsychology

(yet!).

I love this list because so far no one has ever gotten so deadly serious as to

" challenge " another lister over some academic issue. We seem here on this

list

to be more concerned with loving and supporting one another and throwing in a

fact

or two now and then, and for that I thank you all, and love you all,

n Rojas who was, until quite recently, a " fact hound! " Good night all.

[Guest guest]

Hi Jen,

This I did not know! My DH has CAVD, and it was

never explained to us that there was a possibility

that he could have two mutations without presenting

the disease. I was always told that two mutations

= CF. However, this would help explain why both

babies have CF - their chances of having the disease

was raised from 25% to 50% if he was carrying two

mutations instead of one.

Scratching her head now and wondering why the

geneticists failed to mention this little fact...

--- ron88jen@... wrote:

>

> In a message dated 1/16/01 5:27:03 AM,

> pswyd@... writes:

>

> << Also, if someone has more than one defective cf

> gene, they would not be a cf carrier, they would

> have the full-blown disease, since the genes come in

> pairs - like shoes! ;-)

> >>

>

> and to further complicate matters......

> they would have the full blown disease......UNLESS

> they happened to inherit

> two of the more rare mutations that do not always

> CAUSE the full blown

> disease (as in the case of the folks without the

> diagnosis of CF but with

> congentital absence of vas deferans......) (CAVD?)

>

> Jen, who has no idea why she is trying to confuse

> people tonight......

>

__________________________________________________

[Guest guest]

the simple answer is no.

Re: Re: geneticsresponse/reply

No, my question is, can a person carry two CF genes ON THE SAME CHROMOSOME

with a NORMAL " other " chromosome? I think this was what someone was saying

earlier.

***********************

This is a secular list.

***********************

PLEASE do not post religious emails to the list.

--------------------------------------------------

The opinions and information exchanged on this list should

IN NO WAY

be construed as medical advice.

PLEASE CONSULT YOUR PHYSICIAN BEFORE CHANGING ANY MEDICATIONS OR TREATMENTS.

--------------------------------------------------

Our webpage is at http://www.eohio.net/malbright/cfparents.htm

_________________________________________________

Post message: cfparentsegroups

Subscribe: cfparents-subscribeegroups

Unsubscribe: cfparents-unsubscribeegroups

List owner: cfparents-owneregroups

_________________________________________________

WE HAVE A CHAT PAGE!!!

/chat/cfparents

_________________________________________________

[Guest guest]

Hi Jen,

I think it's still 50% and not 75%. This is how I

figure it:

Husband is going to absolutely supply a CF mutated

gene. I could supply either a CF mutation or a

non-CF mutation, so here are the possibilities:

CFa (him) + CFa (me) = CF Child

CFb (him) + CFa (me) = CF Child

CFa (him) + NCFb (me) = r Child

CFb (him) + NCFb (me) = r Child

So, out of 4 possibilities, 2 result in CF and

2 result in carrier status. Looks like 50% to me.

We did get the extended assay, and only

showed one known genetic mutation, and that

mutation showed up in both children, so we assumed

since he showed no symptoms at all of the disease,

that he was merely a carrier, and all the geneticists

we spoke with did not indicate that this was

unusual to see CAVD in a carrier.

Thanks for the info. I'll take it to our geneticist

and see what she has to say.

mommy to and , both wcf and whether

it was a 50% chance or a 25% chance, they got the

raw end of the stick...

--- ron88jen@... wrote:

>

> In a message dated 1/17/01 9:07:49 AM,

> pswyd@... writes:

>

> << I was always told that two mutations

> = CF. However, this would help explain why both

> babies have CF - their chances of having the disease

> was raised from 25% to 50% if he was carrying two

> mutations instead of one. >>

>

> UM....., wouldn't this actually raise their

> chances to 75%????? At

> least, that is how I think it works....

> have you guys had genetics testing? at least the

> genzyme test that tests for

> about 90 mutations?????

> VERY interesting that your hubby has CAVD..... did

> you guys do in vitro?

>

> Jen

>

__________________________________________________

[Guest guest]

Well, I went to my all-knowing physician sister, whose answer is as follows:

Yes, a carrier can carry two different types of mutations (although this is a

moot point if it is on the same gene -- broken is broken, no matter how many

broken pieces). And if it were two mutations on the same gene, the double

defect came from one parent (since each parent gives one gene). IF a carrier

had two different types of mutations each on a DIFFERENT gene, they would

have CF. (i.e., instead of " homozygous delta f508 they might be called

'heretozygous delta f-508, alpha 1209 or something). Get it?

The bottom line appears to be that no one looks for more than one CF gene

since one is sufficient to determine carrier status.