Down Syndrome Community
392 Members
Avatar universal

How does Trisomy 21 change physical characteristics?

I understand that Downs Syndrome is a genetic disorder caused by an extra chromosome, Trisomy 21.  My question is, how exactly does Trisomy 21 so extremely change a person's physical characteristics?  What is it about this extra chromosome that causes all children to have the similiar slant to the eyes, swelled tongue, etc. regardless of race or sex?

It's only a single chromosome against 46 others but is obviously dominant over all other physical characteristics.  How and why?

9 Responses
167426 tn?1254089835
Any abnormality in the gene make up of your body will cause some sort of genetic imbalance. With the extra or part of the Trisomy21 gene, these lead to the various "signs" of Downs. Not that it is dominant, but that it is not supposed to be there. The swollen tongue that you mention is a misdomeaner, the tongue is normal , the mouth is small. As a Downs gets older, some of the visable "signs" are less noticeable. The intelligence scale on the curve, goes from 0 to 180,  the same ratio of intelligence is plotted out  with 90 as the medium, my son clicked in at 75 as a child, but with school, great work facilities and a family that helped him learn, he is pretty independent now and a help in his community. A tax payer, a consumer, an avid camper, traveler. We did not set limits on him so he grew to his ability as he got older. Every person has some ability, an unnurtured  baby will not develope into a "normal"  person either. Half of a persons genes come from each parent, I like to say that my sons extra gene came from God.
Avatar universal
not all children w/ DS have these traits.  The inside of my daughters mouth is small, but her tongue does not protrude.  As a baby and a little girl her traits were not apparent.  Until she started becoming a young teen is when it became more apparent, which made us love her even more.
Avatar universal
I do not like how you say "As a Downs gets older...". My son has DS too and I really HATE to see him being called a "Downs" such as you call them. My son is a human being who happens to have Down Syndrome but he is not a DOWNS.


167426 tn?1254089835
My son is called by his given name at all times, the only people that lable him a Downs are those involved in the government intervention  of his care. Teachers, social workers, doctors, program managers and so forth. I never explain to people that he has Downs.  He is my son.  I was answering the question put to the forum, I have no idea whether this refers to a son or daughter.  I was making a generlized statement about aging.  After raising my son to be very independent and working in the field of adults with disabilities for many years,  I am qualified to speak as I do in generalities.  It means no more to me than saying to someone, that was my Red Headed daughter you saw. Chris is 37 now, when he was born the termanology  for his disability was Mongolian Idiot,  I and many other parents worked very hard to get that lable changed and we did it, along with schooling, closing institutions, raising the level in community awareness.  We fought many battles for you, things that you take for granted now,  we worked hard to win. I made many trips to our state legislature and school board meetings. Now I saw a need for this forum, so I asked for it and got it.  I have served on the ARC board many times, I do this because my son does have Downs Syndrome and since he can't do these things, I do it for him.  So please use this forum in the manner it was set up for, be positive and helpful.  My name is Marty
Avatar universal
Thank you for all you have fought for on the behalf of my family.  My son just had his 1st birthday and is doing quite well.  I am so grateful for what you have done.  I know that I wouldn't even know where to begin if I had to do it all myself.  I also think that Early Intervention is a great resource.
1216082 tn?1266455260
my son chase is 3 months old...he has down syndrome...we found out when he was 4 days old...i couldnt be happier!!!he is actually advanced for his age...he is cuttin his first tooth rite now he was rolling over ate 1 1/2 months etc...has anyone else had this experience? the doctors told me he would be delayed and have so many issues,,,he hasnt had a single problem pop up yet...is that supposed to start at a certain age?
Avatar universal
Lets never be unwilling to make it even better for our kids. I too thank you and all of the folks that put in extra effort to help all people with unomas21.  But it does hurt me to hear anyone, even my sons grandmother , calling my son a downs. Or another person at the senior center she refered to as "a downs was at the center today."  Actually it hurt the first time she said it.  After I corrected her gently, it PMO when she did it again. I jumped her and I don't think she will do it again
Avatar universal
Children with DS are as different from eachother as "normal" people are. My sons little friend who has ds was singing her abcs at age 3. My son couldnt do it until he was 6. He still doesnt read. But will.  Just make sure you provide as many circles for your child as they grow. Preschool, church, boyscouts, any group that you can get into wher he will learn through social interaction. It's even more important to him. It's great when other children can have a positive experience with a person with ds at a young age also.
Avatar universal
I am 40 and had a 1st trimester ultrasound screening everything came out good, measuremnets were all in the normal limits and the trisomy test came out negative as well however the  blood work showed a 4 percent chance of down syndrome should I be worried? My dr doesn't seem to think it is a major problem and tried to reassure me but honestly I am stressing over this even to the point my blood pressure is raisng slowly. It was 142/86 last visit. Any words of advice?
Have an Answer?
Didn't find the answer you were looking for?
Ask a question
Popular Resources
An interview with the co-discoverer of one of the biggest breakthroughs in cancer research
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Here’s how your baby’s growing in your body each week.
These common ADD/ADHD myths could already be hurting your child
This article will tell you more about strength training at home, giving you some options that require little to no equipment.
In You Can Prevent a Stroke, Dr. Joshua Yamamoto and Dr. Kristin Thomas help us understand what we can do to prevent a stroke.