Down syndrome

Mayo Clinic ^ | 2007-04-06 | (Mayo Clinic staff)

[Clive]

Down syndrome

Definition

Down syndrome is a genetic disorder that causes mental retardation and other problems. The condition varies in severity, so developmental problems may range from mild to serious.

Down syndrome is the most common genetic cause of severe learning disabilities in children, occurring in one in every 700 infants. Every year, as many as 6,000 babies are born with Down syndrome in the United States. The condition is named after John Langdon Down, the doctor who first identified the syndrome.

There's no medical cure for this condition. But increased understanding of Down syndrome and early interventions make a big difference in the lives of both children and adults with Down syndrome

Causes

Human cells normally contain 23 pairs of chromosomes. One chromosome in each pair comes from your father, the other from your mother.

The cause of Down syndrome is one of three types of abnormal cell division involving the 21st chromosome. All three abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome. The three genetic variations that can cause Down syndrome include:

Trisomy 21. More than 90 percent of cases of Down syndrome are caused by trisomy 21. A child with trisomy 21 has three copies of chromosome 21 — instead of the usual two copies — in all of his or her cells. This form of Down syndrome is caused by abnormal cell division during the development of the sperm cell or the egg cell.

Mosaic Down syndrome. In this rare form of Down syndrome, children have some cells with an extra copy of chromosome 21, but not all. This mosaic of normal and abnormal cells is caused by abnormal cell division after fertilization.

Translocation Down syndrome. Down syndrome can also occur when part of chromosome 21 becomes attached (translocated) onto another chromosome, before or at conception. Children with translocation Down syndrome have the usual two copies of chromosome 21, but they also have additional material from chromosome 21 stuck to the translocated chromosome. This form of Down syndrome is uncommon.

There are no known behavioral or environmental factors that cause Down syndrome.

Is it inherited?

Most cases of Down syndrome aren't inherited. They're caused by a mistake in cell division during the development of the egg, sperm or embryo.

Translocation Down syndrome is the only form of the disorder that can be passed from parent to child. However, only about 4 percent of children with Down syndrome have translocation. And only about half of these cases are inherited from one of the parents.

In these cases, the mother or father is a balanced carrier of the translocation, which means he or she has some rearranged genetic material, but no extra genetic material. A balanced carrier has no signs or symptoms of Down syndrome, but he or she can pass the translocation on to children.

The chance of passing on the translocation depends on the sex of the parent who carries the rearranged chromosome 21:

If the father is the carrier, the risk is about 3 percent.
If the mother is the carrier, the risk is about 12 percent.

Risk factors

Some parents have a greater risk of having a baby with Down syndrome. Risk factors include:

Advancing maternal age. As a woman's eggs age, there's a greater inclination for chromosomes to divide improperly. So a woman's chances of giving birth to a child with Down syndrome increase with age. By age 35, a woman's risk of conceiving a child with Down syndrome is 1 in 385. By age 40, the risk is 1 in 106. And by age 45, the risk is 1 in 30. However, most children with Down syndrome are actually born to women under age 35 because this younger group of women has far more babies.

Mothers who already have one child with Down syndrome. Typically, a woman who has one child with Down syndrome has about a 1 percent chance of having another child with Down syndrome.

Parents who are carriers of the genetic translocation for Down syndrome. Both men and women can pass the genetic translocation for Down syndrome on to their children.

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[Clive]

Alan Colmes is an idiot.

He is a party apparatchik whose principle skill is an ability to memorise and deliver talking points by rote.

[wendy1946]

They are coming within a fraction of letting these people lead normal lives these days entirely via diet.

[raybbr]

Alan Colmes SHOULD be shunned and ostracized for the horrible creature he is. He won't be though. They (the lunatics in the U.S.) will still listen to him as some sage.

The people on the left like him are truly deranged.

[seekthetruth]

My husband and I have friends who had three children, and one with downs. They ALL graduated from college, and the downs child is now working in the business field. :)

[Dilbert San Diego]

Liberals, go ahead and make my day. If they politicize Sarah Palin’s baby in any way, we need to call them on it.

And it’s not just the Down’s syndrome aspect of it. On one talking head show, liberal Cokie Roberts said that women are going to be angry if anyone brings up issues of childcare for that baby, and how can Sarah campaign with a baby, how will she be Vice-President with a baby, etc. Cokie said that all women not just the Republican women will be taken aback if any discussion in that area happens in this campaign. This issue needs to be left alone by the Democrats.

[TribalPrincess2U]

Guess he doesn’t know much about “women”.

Can’t show this too much....
Compare these two, side by side.

http://www.justsaynodeal.com/

[fullchroma]

I worked for years with a woman with Down Syndrome.

She prepared deserts at a very nice restaurant, the Tabard Inn, in Washington DC. She “plated” pie or cake slices and garnished each with beautiful swirls of whipped cream and sliced berries or mint. She browned creme brulee with a little blow torch that the rest of us would have been afraid to use. She was a visual artist of a sort.

She took the bus to and from work, was always on time and rarely took sick days. Her husband was similarly disabled and equally self-sufficient. She had a wonderful sense of humor and was always kind. We all loved her.

[TribalPrincess2U]

Oh yeah, they’re worried about “the baby” now.

Another one won’t wash.

[TMSuchman]

I am a proud father of a son with Down Syndrome! My son Lance is my little buddy! he is also an early intervention child, that is we started physical therapy with him when he was a week old [streching, and flexabality therapies]. He is now quite a Special Olympics runner & is working on becoming a long distance runner [I had to buy a 3 wheeler just to keep up with him, beacuse he is sssssoooo fast! ;>)
He is in school that mixes him with special needs kids & regular kids. Lance takes music,gym,art,lunch and recess with the regular kids & his academic classes with his special needs class!

AND I WILL DEFEND HIM TO THE DEATH ANYBODY WHO DISRESPECTS HIM TOO!

[backhoe]

Thank you, my friend.

My wife- the Miss Emily I mention-- was supposed to be a Down's baby, and this was in the days when abortions were routine for this.

Fortunately, her Doctor simply gave her Mom the information, and she decided to carry her to term.

Ironically, she tests at high genius level...

You may also recall that my first wife was severely handicapped, so factor that in to this:

I would never tell another what to do in either circumstance, for everyone reacts and behaves differently- but I'm glad Miss Emily made it, I had a full and good marriage with my long-dead first, and God bless those who wish to give life to one who may be handicapped-- they still are human, and have worth.

Oh! And after years of hiatus, I'm running a live thread for Governor Palin, here:

Sarah Palin- links, from the beginning:

[Always Right]

She had a wonderful sense of humor and was always kind. We all loved her.

My cousin has downs. Sweetest person you will ever meet. Always a joy to be around. I admire my aunt and uncle for not letting her die. With all her medical problems, all the doctors said she could not survive. That was over 40 years ago.

[mware]

full, my brother is a the director of a mental health clinic and deals with Down's Syndrome people all the time.

They build a cafe, where they work at various jobs within the cafe.

They take their responsibilities very seriously. My brother tells me if one of them is absent from work they actually check on them because they rarely miss work.

They are also the most honest type of people almost incapable of lying to you.

You might not like what they say, but they will be honest.

[Rokurota]

Athlete with Down's Syndrome runs 99 yards for a touchdown.

[yazoo]

I did some work on a special olympics program in North Carolina this year and met a lot of adults and children with Down’s Syndrome. The level of disability varied widely but every one of them was a joy to be around. Moreover, the commitment and effort by their parents to give them everything possible in life was inspiring.

[Alia]

I back-up everything you wrote about Downs Syndrome, specifically in adults. I’m around them a lot. Some of the best workers a company could employ.

[Alia]

Correction: DOWN Syndrome.

[mware]

Wow did my screen get blurry.

[fullchroma]

Go Lance!! You are blessed.

[fullchroma]

It’s always good to question authority!

The doctors told my cousin and her husband that their disabled (not Down’s) newborn wouldn’t last a day or two and advised them not to hold her or take her home — just leave her there to die. They took her home.

That was 25 years ago. Sophie is a beauty in every way, graduated from high-school and now works at a bank.

[fullchroma]

You might not like what they say, but they will be honest.

That's true!