genetic question

June 19, 2000

Amy

In my search for finding out about hypochondroplasia, I did find and article

about a girl who was born with both domanant genes of

achondroplasia-hypochondroplasia. In this case the little girl did not live

long. I have miss placed it at the moment but if you would like to read it

I could try to find it for you.

Robin

>I was thinking about the different types of dwarfism, and i was

>wondering...

> for example.. if my brother, who has hypochondroplasia, marries (which

>won't

>be for a while, lol...) a woman who has achondroplasia, what are the odds

>of

>the child having hypochondroplasia or having achondroplasia? And since the

>parents would not both have the same type of disorder, there would be no

>chance of a DD child, right? But is there a chance of the baby still

>getting

>both dominant genes? Would the baby die soon after birth like a DD child? I

>tried to see if there was any info at:

>www. dwarfism.org/medical, the Human Genome Database, and the Greenberg

>Center for Skeletal Dysplasias- Hopkins Hospital, but i could not find

>any. Also if someone who has pseudoachondroplasia marries someone who has

>achondroplasia what are the odds like? Just a wondering soul over here.

>Sincerely,

>Amy

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June 20, 2000

Hi, Amy... I was also wondering something myself. I have

pseudoachondroplasia and the father of my expectant child is average sized.

I have been informed that I have a 50/50 chance of having a child with

pseudoachrondroplasia, but will the child have the same type of

pseudoachondroplasia that I have? I know there are several types of pseudos

- I am 4'3, but I know some pseudos that are 3'10. I am doing my best to

inform my doctors, but they seem to think they are going to be able to

determine if the child is going to be LP while still in the womb. I wasn't

diagnosed until I was 5 1/2... and I have read that most are not diagnosed

until 2 years of age. Any insight or advice anyone has to offer would be

greatly appreciated!

Thanks,

Greenville, SC

Genetic Question

I was thinking about the different types of dwarfism, and i was wondering...

for example.. if my brother, who has hypochondroplasia, marries (which

won't

be for a while, lol...) a woman who has achondroplasia, what are the odds of

the child having hypochondroplasia or having achondroplasia? And since the

parents would not both have the same type of disorder, there would be no

chance of a DD child, right? But is there a chance of the baby still getting

both dominant genes? Would the baby die soon after birth like a DD child? I

tried to see if there was any info at:

www. dwarfism.org/medical, the Human Genome Database, and the Greenberg

Center for Skeletal Dysplasias- Hopkins Hospital, but i could not find

any. Also if someone who has pseudoachondroplasia marries someone who has

achondroplasia what are the odds like? Just a wondering soul over here.

Sincerely,

Amy

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May 15, 2001

In a message dated 5/14/2001 7:02:22 PM Pacific Daylight Time,

liliwigg@... writes:

> Lamar, or anyone else, do you think it is possible for CMT to have run

> through a family until one day it becomes to slight, it is almost not

> there? Then in the next generation is is NOT for sure? Maybe this sounds

> wierd, but I was just thinking if CMT can burn itself out,

> generationally and mutatingly speaking.

>

> ~ Gretchen

>

Good question G. I have heard CMT was discovered 100 years ago. I would like

to know if that first family is still around.

jenny

May 15, 2001

I wonder if the CMT gene is as strong in a racially mixed couple??

jenny

May 15, 2001

In a message dated 5/14/2001 10:11:54 PM Pacific Daylight Time, lls@...

writes:

> ,

> I am sure their names are in the record, and it is usually easy to trace

> someone from the 1880's to today. You probably won't find EVERY descendant,

> but will most. It actually becomes harder after WWII. People are much more

> mobile, and often live in dozens of places during their life. Public

> records do not contain as many details as they once did. Paper trails are

>

Anyone wanna trace one of the first families with me?

May 15, 2001

Lamar, or anyone else, do you think it is possible for CMT to have run

through a family until one day it becomes to slight, it is almost not

there? Then in the next generation is is NOT for sure? Maybe this sounds

wierd, but I was just thinking if CMT can burn itself out,

generationally and mutatingly speaking.

~ Gretchen

May 15, 2001

In a message dated 5/14/2001 10:33:37 PM Pacific Daylight Time, lls@...

writes:

> ,

> Lamar here,

>

> No difference. The gene is there or not, and no " weaker " in any one race or

>

I was thinking tho like when a baby is born early they have better chance of

living if they are mixed. So if say a black man no CMT and a white woman with

CMT has a baby what gene would be stronger?? I think we should do a poll.

jenny

May 15, 2001

Your thought would be wonderful!!! Let's hope and pray CMT does burn itself

out, or there is a cure!

----- Original Message -----

From: Gretchen Glick <liliwigg@...>

< >

Sent: Monday, May 14, 2001 8:37 PM

Subject: [] genetic question

> Lamar, or anyone else, do you think it is possible for CMT to have run

> through a family until one day it becomes to slight, it is almost not

> there? Then in the next generation is is NOT for sure? Maybe this sounds

> wierd, but I was just thinking if CMT can burn itself out,

> generationally and mutatingly speaking.

>

> ~ Gretchen

>

May 15, 2001

Gretchen,

Lamar here,

NOPE. The genetic defect is there or not there. If it is present it can be

passed on. If it is not, it can't be transmitted. It is not " watered down "

like some things. For instance, skin color from a racially mixed union

becomes essentially undetectable after 4-5 generations. Now, some forms of

CMT are autosomally recessive. BOTH parents would be without symptoms but

carry the same recessive gene. There could be generations without any

symptoms until a male and female with the same abnormality produced

offspring. This does happen, but is uncommon for many reasons. With

increased population flow and numbers the probability that any two

particular individuals will ever encounter each other and produce offspring

decreases. For instance when California had only 100 people the probability

was higher than today. The other main reason is that these types are usually

VERY severe and strike in infancy and many die in childhood. Therefore,

autosomally recessive forms are usually limited to indigenous populations

where intermarriage is not unusual. It is found mainly in tribal peoples,

isolated from outsiders. It does happen, but is rare.

You also have a possibility of spontaneous mutations. I have asked several

CMT researchers about this. Though many with CMT do not know of a family

history, it is very likely it was there. Symptoms may have been so minimal

that it was never noticed. Since some do not show symptoms until later in

life, the person could have died before symptoms were noticed. While no

reflection to anyone in the group, there are cases where the biological

father is not known. Let's face it, it happens. CMTX can go unnoticed for

generations. Then, there is a possibility of a true mutation, but these are

very rare. That is what the CMT researchers I have asked said, and it

agrees with genetics as I was taught.

It was mentioned at a conference I attended, that some types SEEM to show a

worsening of symptoms as generations progress. While not so of every

individual in the family, the majority of children will be worse than

parents. This is not true of all families or types. That could be

partially accounted for by the fact that people are weaker than our

forefathers (and we live longer-you were strong or died). I know of few

that could walk hundreds of miles in a wilderness, cut trees, build a home,

and survive. In a shorter perspective, many adults grew up without central

heat and air. I did, and it did not really worry me. Now, that my body has

become accustomed to it, I suffer without it. Very likely many of us have

had medical problems we would have died from even 50-75 years ago. So, our

CMT would not have progressed as far.------All of these could play a part,

but still the indication is that for some it gets worse every generation.

----- Original Message -----

From: Mommy2Adam@...

Sent: Monday, May 14, 2001 11:23 PM

Subject: Re: [] genetic question

In a message dated 5/14/2001 7:02:22 PM Pacific Daylight Time,

liliwigg@... writes:

> Lamar, or anyone else, do you think it is possible for CMT to have run

> through a family until one day it becomes to slight, it is almost not

> there? Then in the next generation is is NOT for sure? Maybe this sounds

> wierd, but I was just thinking if CMT can burn itself out,

> generationally and mutatingly speaking.

>

> ~ Gretchen

>

Good question G. I have heard CMT was discovered 100 years ago. I would

like

to know if that first family is still around.

jenny

May 15, 2001

,

I am sure their names are in the record, and it is usually easy to trace

someone from the 1880's to today. You probably won't find EVERY descendant,

but will most. It actually becomes harder after WWII. People are much more

mobile, and often live in dozens of places during their life. Public

records do not contain as many details as they once did. Paper trails are

there, but harder to find.

----- Original Message -----

From: Mommy2Adam@...

Sent: Tuesday, May 15, 2001 12:41 AM

Subject: Re: [] genetic question

In a message dated 5/14/2001 9:11:47 PM Pacific Daylight Time,

lls@...

writes:

> Very

> likely it had been around for many generations, possibly hundreds of

years.

> Virtually all diseases were around long before they were named.

>

To bad the doctors didn't follow CMT in the first people diagnosed.

Y,.-:*'``'*::*:*:-.,_,.-:**:-Y.-:*:*::-.,_,.-:*'``'*:-.,,.Y

May 15, 2001

,

Lamar here,

No difference. The gene is there or not, and no " weaker " in any one race or

national origin.

----- Original Message -----

From: Mommy2Adam@...

Sent: Tuesday, May 15, 2001 01:05 AM

Subject: Re: [] genetic question

I wonder if the CMT gene is as strong in a racially mixed couple??

jenny

May 15, 2001

-----Original Message-----

From: Mommy2Adam@... <Mommy2Adam@...>

< >

Date: Tuesday, May 15, 2001 12:48 AM

Subject: Re: [] genetic question

In a message dated 5/14/2001 10:33:37 PM Pacific Daylight Time, lls@...

writes:

> ,

> Lamar here,

>

> No difference. The gene is there or not, and no " weaker " in any one race or

>

I was thinking tho like when a baby is born early they have better chance of

living if they are mixed. So if say a black man no CMT and a white woman with

CMT has a baby what gene would be stronger?? I think we should do a poll.

jenny

>>>>, they would still have a 50/50 chance of having a child with CMT.

Ones not stronger then the other. ~>Becky M.

May 15, 2001

The baby inherits 23 chromosomes and thus all the genes from each parent to

form the diploid number of chromosomes we have of 46 in our bodies. If the

baby inherited the gene, it was from either the father or the mother. If

the baby inherited the gene from either the father OR the mother, it

inherited the entire gene and the anomaly would be the same as in the parent

that had it. That is why genetic testing is possible. If the gene changed

every generation, they would not know what to look for. I assure you that

if any race without CMT and any other race with CMT had a child, the child

would either have the same gene or would not have it. You can not inherit

just a little of it. According to the conference I attended and all I have

read, there is no racial difference in how any given type affects the

individual in any race. There have been some types that have not been found

in some races, but if that race mixed with one that had it the offspring

would stand the same chance as any other.

----- Original Message -----

From: Mommy2Adam@...

Sent: Tuesday, May 15, 2001 01:53 AM

Subject: Re: [] genetic question

In a message dated 5/14/2001 10:33:37 PM Pacific Daylight Time,

lls@...

writes:

> ,

> Lamar here,

>

> No difference. The gene is there or not, and no " weaker " in any one

race or

>

I was thinking tho like when a baby is born early they have better chance

of

living if they are mixed. So if say a black man no CMT and a white woman

with

CMT has a baby what gene would be stronger?? I think we should do a poll.

jenny

May 15, 2001

In a message dated 5/14/2001 11:37:00 PM Pacific Daylight Time,

rmax@... writes:

> >>>>, they would still have a 50/50 chance of having a child with CMT.

> Ones not stronger then the other. ~>Becky M.

>

May 15, 2001

In a message dated 5/14/2001 11:37:00 PM Pacific Daylight Time,

rmax@... writes:

> >>>>, they would still have a 50/50 chance of having a child with CMT.

> Ones not stronger then the other. ~>Becky M.

>

I bet there is a diffrence. The stronger gene wins.

jenny

May 15, 2001

But I am saying here is if you have CMT and your not the dominate gene then

that reduces your chances. Like if you have blue eyes and you have a biracial

child that child will likely have brown eyes. That is the stronger gene.

J

May 15, 2001

,

Lamar here,

Again, there is no " stronger " gene. The egg contains 1/2 of the genes the

female has on it's 23 chromosomes. The sperm contains 1/2 of the genes the

father has on it's 23 chromosomes. They combine in fertilization to give an

embryo with 46 chromosomes that we all have. If the sperm or egg gets the

chromosome with the CMT gene, it does; and if it does not, it does not.

There is no half way. Visualize it as an apple. One side has a tiny rotten

spot, the rest of the apple is perfect. Cut the apple in half. One half

will have the bad spot and one half will not. That is the basis of what

happens when the egg or sperm is formed. Using this if the good half of the

apple combines with a good half of another apple you have two good apple

halves. If the half with the rotten spot combines with a good half of

another apple you have 2 apple halves but still have the rotten spot. With

CMT, if the egg or sperm has the CMT gene it will pass to the child, if they

do not it will not.

The only other possibility would be where an individual had more than one

type of CMT. This is genetically possible if at some point both a mother

and father of a child each had a different type of CMT. (i.e.: if mother

had Type 1 and Father Type 2--the child could have Type 1, or have Type 2,

or have both types, or be CMT free.) They do not know with certainty, but

it would stand for reason the child with BOTH types would have more severe

symptoms. I asked Athena Labs about this a couple of years ago. They

agreed that it was possible, but to that date no individual had been found

with more than one type. There could be some out there, as not all have

been tested and tests do not exist for every type.

Remember, you can't be " almost alive " , or a " little pregnant " . You get all

the gene or none of it.

----- Original Message -----

From: Mommy2Adam@...

Sent: Tuesday, May 15, 2001 11:51 AM

Subject: Re: [] genetic question

In a message dated 5/14/2001 11:37:00 PM Pacific Daylight Time,

rmax@... writes:

> >>>>, they would still have a 50/50 chance of having a child with

CMT.

> Ones not stronger then the other. ~>Becky M.

>

I bet there is a diffrence. The stronger gene wins.

jenny

May 15, 2001

-----Original Message-----

From: Mommy2Adam@... <Mommy2Adam@...>

< >

Date: Tuesday, May 15, 2001 3:25 PM

Subject: Re: [] genetic question

But I am saying here is if you have CMT and your not the dominate gene then

that reduces your chances. Like if you have blue eyes and you have a biracial

child that child will likely have brown eyes. That is the stronger gene.

J

>>>>>>> if you have CMT, you have that gene. Its with you no matter what.

Now as to the eye color. Brown eyed female/male, brown eyed male/female will

" most likely " not alway's have brown eyed children. Blue eyed female/male and

blue eyed male/female will " most likely " not alway's have blue eyed children,

blue eyed male/female brown eyed female/male have a 50/50 chance of having a

child with blue eyes or brown eyes. Same as with CMT 50/50. I have a cousin

with one blue eye and one brown eye. I have one dark brown eye and one that is

lighter hazel, so does my son with CMT. There is no stronger gene with CMT, you

have it 100% or you don't have it 100% and the chance of passing it on no matter

the race mixed with is the same 50/50. There is no domination of that gene. Its

not stronger in some, less in others. Its not deluted by time or race or

intermixing of races. Confusing isn't it! ~>Becky M.

May 15, 2001

Lamar here,

BUT CMT genes are either autosomally dominant or sex linked except for the

rare autosomally recessive forms usually found in tribal communities. That

is why only autosomally recessive types and CMTX are the only types that can

be recessive.

----- Original Message -----

From: Mommy2Adam@...

Sent: Tuesday, May 15, 2001 04:28 PM

Subject: Re: [] genetic question

But I am saying here is if you have CMT and your not the dominate gene

then

that reduces your chances. Like if you have blue eyes and you have a

biracial

child that child will likely have brown eyes. That is the stronger gene.

J

May 15, 2001

Becky,

Lamar here,

Also we must consider that the eye color and hair color is does not depend

on one gene. Over 100 are involved in each--that is why the wide range of

shades. CMT is a specific defect on a part of a single gene (though the

different types can be on different genes).

----- Original Message -----

From: Maxwell

Sent: Tuesday, May 15, 2001 04:57 PM

Subject: Re: [] genetic question

-----Original Message-----

From: Mommy2Adam@... <Mommy2Adam@...>

< >

Date: Tuesday, May 15, 2001 3:25 PM

Subject: Re: [] genetic question

But I am saying here is if you have CMT and your not the dominate gene

then

that reduces your chances. Like if you have blue eyes and you have a

biracial

child that child will likely have brown eyes. That is the stronger gene.

J

>>>>>>> if you have CMT, you have that gene. Its with you no matter

what. Now as to the eye color. Brown eyed female/male, brown eyed

male/female will " most likely " not alway's have brown eyed children. Blue

eyed female/male and blue eyed male/female will " most likely " not alway's

have blue eyed children, blue eyed male/female brown eyed female/male have a

50/50 chance of having a child with blue eyes or brown eyes. Same as with

CMT 50/50. I have a cousin with one blue eye and one brown eye. I have one

dark brown eye and one that is lighter hazel, so does my son with CMT.

There is no stronger gene with CMT, you have it 100% or you don't have it

100% and the chance of passing it on no matter the race mixed with is the

same 50/50. There is no domination of that gene. Its not stronger in some,

less in others. Its not deluted by time or race or intermixing of races.

Confusing isn't it! ~>Becky M.

May 15, 2001

In a message dated 5/15/2001 2:14:05 PM Pacific Daylight Time,

rmax@... writes:

> I have one dark brown eye and one that is lighter hazel, so does my son with

> CMT. There is no stronger gene with CMT, you have it 100% or you don't

> have it 100% and the chance of passing it on no matter the race mixed with

> is the same 50/50. There is no domination of that gene. Its not stronger in

> some, less in others. Its not deluted by time or race or intermixing of

> races. Confusing isn't it! ~>Becky M.

>

I think we need to test this out. Any volunteers?

May 15, 2001

-----Original Message-----

From: Lamar son <lls@...>

< >

Date: Tuesday, May 15, 2001 4:28 PM

Subject: Re: [] genetic question

>>Right but trying to simplify things to compare to make it easier to understand

the CMT gene. Also, isn't it different with genes that determine pigmentation?

~>Becky M.