Re: UPD7 explanation, incidence rate, etc.

[Guest guest]

, Ken and Judith and others -

Sadly, your geneticist did somewhat misinform you. Uniparental

disomy 7 (which is when a child inherits both chromosome #7s from

their mother instead of the normal one from mom and one from dad)

does NOT " Cause " -Silver Syndrome. In fact, this same UPD7

trait has been found in several other short-stature disorders, as

well. However, it is a link, and geneticists are still

investigating it, because of the maternal link.

Regarding the incidence rate of 10% for UPD7 in RSS children. Ken,

I think that the listserve is probably not the ideal testing ground,

as many parents of more mildly-affected children tend to drop off

the listserve.

Of the 101 families whose children have seen Dr. Harbison at the

MAGIC Convention, received positive RSS diagnosis confirmations, and

then filled out the comprehensive survey for the upcoming Guidebook,

we actually have a startling 16% who have tested positive for UPD7.

However, 56 children of the 101 were NOT tested. Assuming NONE of

those children were UPD7, we would have a 7% incidence rate. So the

incidence rate for our group is somewhere between 7% and 16%.

Numerous studies conducted over the last 30 years or so have

consistently found an average of about 10% for the incidence rate of

UPD7. More interesting to me, however, and I think I posted this a

while back, is the fact that some recent studies have looked at the

characteristics of UPD7 children. They have found that matUPD7 RSS

children typically do NOT have the stereotypical triangular shaped

face. They have more of a boxy square face, which may cause these

children to NOT be diagnosed as RSS.

However, these studies have also found that although

their " phenotype " of RSS is more mild for matUPD7 (the way they

look), these matUPD7 children often have more severe developmental

problems than normal chromosome 7 RSS children.

I am telling you, if we could hire a researcher/statistician, we

could have a FIELD day writing and publishing!!!!! Go fundraising!!!

Salem

>

> Thank you so much to everyone who replied to my email regarding my

> son with RSS. I hope everyone had a good Thanksgiving. I would

like

> to continue now about my experience with RSS and hopefully this

can

> help others.

>

> If you already know this, please disregard, but I just found out

why

> RSS occurs. I became pregnant last November and experiened several

> problems - this time without the help of fertility. I began

bleeding

> in my 9th week and went to a doctor who specializes in high-risk

> pregancy for gestantional diabetes, rare genetic disorders etc.

and

> has high-tech scanning equipment. It turned out I had a bleeding

> cyst. This did raise a question about if I would have another RSS

> child so I was sent to a geneticist.

>

> She explained to me in great detail how RSS occurs - the easiest

way

> to explain it would be that within our DNA, chromosome 7 needs to

> have a male and female gene when making up your DNA and in the

case

> of RSS, same sex genes are the reason for a birth occuring with

RSS.

> Chromosome 21 is the same way which is why some babies are born

with

> Down Syndrome. Although you can do an amnio for Down Syndrome, you

> cannot find out about RSS until the baby is born when they can

draw

> blood and do a UPD7 test to confirm for RSS.

>

> Along with the help of my specialist, he could also use the scan

to

> look for a curved spine and triangular face features on the screen

> which would be signs of RSS. It was amazing how both doctors came

> together to help me. I gave birth to a healthy baby girl in July.

>

> I thank all of you who read my first emailed and replied to me. I

am

> so grateful a group like this exists.

>

>