Down Syndrome Day

Down Syndrome Day

Today, 3/21, is World Down Syndrome Day. Also known as Trisomy 21, because it involves three copies of chromosome 21 instead of the usual two (see image), Down syndrome is the most complex of genetic disorders that is compatible with survival (other trisomies are more common, but are lethal). Even Down syndrome is associated with ~50% lethality of embryos. In the US, 1 in 691 babies is born with Down syndrome.

Too much of a good thing: Anywhere from 300 to 500 genes have altered levels and function, resulting 80 or 90 possible symptoms and an instantly recognizable phenotype (physical appearance). For example, patients have a 1 in 5 chance of developing a hole in the heart, compared to an incidence of 1:10,000 in the normal population. Down syndrome is extraordinarily complex, and my friend and colleague Roger Reeves has dedicated his career to helping patients with his research.

Cerebellar size: Dr. Reeves showed that the reduced size of the cerebellum in patients was due to defects in the sonic hedgehog signaling pathway. Using a drug that activated this pathway, he was able to restore the number of cerebellar cells to normalcy in a mouse model of Down syndrome, pointing to a therapeutic potential for the central nervous system deficits in patients.

Tweaking circuits: In the hippocampus—that part of the brain that’s used to navigate landmarks and fix memories, Down syndrome patients show an excess of inhibitory pathways compared to excitatory ones. A drug that is already FDA-approved works wonders on mice with the equivalent of Down syndrome, restoring balance to their brain. This drug is now in clinical trials for  Down syndrome patients.

It’s not all bad: Research on Down syndrome has broad impact. For example, having three copies of a tumor suppressor gene means that patients have a 93% lower incidence of developing certain cancers. This insight could help treat cancers in the general population. Plus, as Roger likes to say, if you know anyone with Down syndrome, they tend to be pretty interesting individuals in their own right.

For more on Roger’s research:

#ScienceEveryday #DownSyndrome  

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114 Responses to Down Syndrome Day

  1. Guy Eastwood says:

    It always beguiles me how biology is simultaneously so incredibly robust and durable and yet so delicate at its core.

  2. Just for you to know, today it’s 21/3 (well, already 22/3, here), not 31/3.

  3. Slight typo at the start (you mean 3/21?). Thanks for the enlightenment.. I hadn’t known about World Down Syndrome Day till now.

  4. Rajini Rao says:

    I agree! Why should one extra copy of a gene be so bad, right?

  5. Rajini Rao says:

    Oops, yes, thanks Raphael Ndem !

  6. Guy Eastwood says:

    It’s like some branches of maths, a difference of one (or even minutely less) destroys entire calculations. Like if the cosmological constant were a billionth different the universe may well not exist, yet it does and it’s massively robust (within our understanding of it). Just that tiny squillionth of a deviation, though and it’s be foop and not there, or utterly different.

  7. Rajini Rao says:

    Thanks, Víktor Bautista i Roca . Fixed! You guys have sharp eyes 🙂

  8. Rajini Rao says:

    Guy Eastwood , I would never have made that comparison, and you make a great point. Complex systems are in delicate balance whether cosmological or biological.

  9. By the way, today there was around here an article about a trisomy in corn that gave the plants a higher resistance to aluminum loaded soil.

  10. Rajini Rao says:

    Víktor Bautista i Roca , many plants have polyploidy, where the entire set of chromosomes is duplicated or multiplied. Is the corn example of just one chromosome or the whole set, do you recall?

  11. Right now I’m looking for the article, Rajini Rao 

  12. Lexie Chaban says:

    That’s kind of cool, in a way 😮

  13. I love this image of the karyotype and will add it to my collection (slides I show students).   We also talk about Edward, Patau, Turner  and Klinefelter Syndome.  I’ve always wondered why the trisomy and monosomy disorders were given those proper names and not just named by their number, something my students would find much easier to remember.  

  14. Rajini Rao says:

    Lexie Chaban , sometimes, people get upset when researchers get excited about a disease..because the underlying science is cool, even if it does cause suffering. There’s nothing more exciting (!?) than to work on a gene out of curiosity or a hunch, and then have a geneticist call you from across the world to say that a defect in your favorite gene causes some disease. Hopefully, people understand our perspective 😛

  15. Jim Preis says:

    Rajini Rao Thank you so very much for this share.  My son who is 6 now has Down Syndrome.  Excellent and encouraging information!!!

  16. Rajini Rao says:

    That’s wonderful to hear, Austin pollard ! Thank you for adding your personal voice to this and helping us understand. Trisomy 21 is named after John Langdon Down, a British doctor, who diagnosed it in 1866. He should have been named Dr. Up since Down syndrome kids people are reputed to have the most gentle and happy personalities 🙂

  17. Rajini Rao says:

    Jim Preis , I hope you found this somewhat useful. Most of what I know comes from sitting in on seminars from the Reeves lab that is down the hall from ours.

  18. Rajini Rao Argh! it was almost impossible to find! They don’t call corn corn, but maize, don’t say trisomy, but triple copies of gene, and the mention to Aluminium is just “Al” on an image. Here it is:

    Triple copies of gene make maize tolerant to toxic soil

    By Krishna Ramanujan

  19. Jim Preis says:

    Rajini Rao Small world.  My grandfather and namesake, James Thomas Means, was an OBGYN at JH for 20 years in the 1960’s and 70’s. 🙂

    I’ve always enjoyed your posts and this one was the best.

    Thank you again!!!

  20. In the bible it says that people like that have an automatic ticket to heaven…Something like that, but after reading that passage, I would be happy if I had a kid with Down Syndrome.

  21. Rajini Rao says:

    Jim Preis , good to know..Hopkins is a truly wonderful place to practice and do research. I hope he enjoyed his time here.

    Aaron Guerrero , aww..that is a sweet thought 🙂

  22. «…since Down syndrome kids are reputed…»

    Are Down syndrom adults not reputed so? This is something that upsets me. When people talks about some syndromes they assume they only afect kids. Autistic children, Down kids… as if they’d never grow up. And it is on growing up when many problems may arise. I mean, yeah, you may have learnt how to live in society by then, but you are probably with no parents to back you up and confronted to a society that doesn’t accept difference.

    Sorry for the rant, this “kid” was harmless and with no ulterior intention, of course, but as you can see this upsets me.

  23. Rajini Rao says:

    Good point, edited to be more inclusive, Víktor Bautista i Roca .

  24. Rajini Rao says:

    Austin pollard , Viktor was being supportive of all people with DS, not just kids.

  25. Rajini Rao About the maize, you were right, it’s three copies versus one: «But when she examined copy number variation, she found the aluminum-tolerant plant had three copies, while the intolerant plant had only one copy of the MATE1 allele.»

    Austin pollard Sorry???

  26. G Money says:

    And, why would we need aluminum resistant plants?  Could it be the weather modification practices that spray aluminum particulates into the atmosphere?  Problem, reaction, solution…eek

  27. G Money From the same article: «Acidic soils dissolve aluminum from clays in the soil, making it toxic to plant roots in half the world’s arable lands.»

  28. Rajini Rao says:

    Víktor Bautista i Roca , I’ve actually heard about this particular research at a conference because the maize aluminium resistance is due to an aluminium transporter and my work is on ion transporters.

    Re. the copy number variation, these can be either beneficial or harmful depending on the gene. But when an entire chromosome is extra, it ends up being deleterious because so many genetic networks are impacted. If the whole set of chromosomes is multiplied, as happens in plants, it enhances fitness.

  29. G Money says:

    Víktor Bautista i Roca

    Acidic soils from…?

  30. Rajini Rao says:

    G Money : acidic soils are  naturally occurring -even without human help 😉

  31. G Money says:

    are acidic soils so prolific that we need to develop aluminum resistant plants?

  32. Ernest W says:

    Cool research and promising treatments.

  33. G Money Same quote: «Acidic soils dissolve aluminum from clays in the soil, making it toxic to plant roots in half the world’s arable lands.»

  34. Rajini Rao says:

    G Money , yes they are . Google it to confirm. Here is one link:

    You need to stop being so suspicious of plant biologists 🙂

  35. Mary T says:

    Excellent and very informative post Rajini Rao ~

  36. Rajini Rao says:

    Thanks, Mara 🙂

    Elena Weingarten , the image is of a karyotype. It is a spread of all the human chromosomes.

  37. G Money says:

    Hopefully, we are all aware that acidic soils naturally occur, but my question: is it such a problem that we need to manipulate plant genetics specifically to accommodate aluminum proliferation in these acidic soils.  What percentage of our farm land are acidic soils?  My point is that acid rain and weather modification are contributory, nothing more.

  38. Rajini Rao says:

    G Money , check out the links that I provided and you can convince yourself of the answer since you are not taking my word for it.

  39. Austin pollard Very nice Austin, I know forst hand waht you are talkin about 

  40. Joe Weddle says:

    keep calm

    it’s only an extra chromosome!

  41. oooooooo i like pretty colours

  42. Rajini Rao says:

    Zachary Young , science is even sexier 😉

  43. Eric Hopper says:

    Thank you. I remember some of this from elementary school, but I hadn’t followed up on the research since them. grin And, of course, the version they gave us in elementary school was simply ‘extra chromosone’. Which I’m guessing everybody but me forgot anyway.

    I do know that at the time they had absolutely no clue about sonic hedgehog or its role in embryo development.

  44. Rajini Rao says:

    Eric Hopper , the name sonic hedgehog is a quirky joke. The original gene, found in Drosophila (fruit fly) was named hedgehog because the mutant was covered in prickles. It turned out to have three versions in human, so they were named desert hedgehog, Indian hedgehog and sonic hedgehog (after the video game) 🙂

  45. Eric Hopper says:

    Rajini Rao – Thanks for the story and the link. 🙂 I’ve read a bunch of sci am articles that have mentioned sonic hedgehog, but I don’t think any of them told the story of how that name came to be. 🙂

  46. well we r learning that in our science class and I hate it

  47. I have 2 2nd cousins with downs and a 3rd cousin with downs and my love for them is equal.  God Bless Them!!

  48. Oh My Gosh my mom is a school psychologist and my cousin have severe autism and down syndrome. I had no idea about 3/21!

  49. Yash Kommula says:

    Learned this this yr in Bio

  50. So here’s a science-y question.  Most of the treatments you mention deal with treating the effects of the expression of the genes.  Since human females deactivate one of their X chromosomes as a rule (Barr bodies), what are the odds that we can find the mechanism for chromosome deactivation and apply it to that 3rd chromosome before the developmental problems begin. 

  51. You all make it sound like a bad thing is it?

  52. Rajini Rao says:

    Shannan Muskopf , that’s an interesting idea! Let me dig around and see what is known about the molecular mechanism of X-inactivation (epigenetics, I’m guessing, but how is it controlled?).

    michael dicarlo , make what a bad thing?

  53. A man with this syndrome was killed a day b4 this day.

  54. Jacinda Chen says:

    Really? I just found out what it was yesterday.

  55. Atul Solanki says:

    Good morning friend

  56. Rajini Rao says:

    I learned something important, thanks for your thoughts on this Elizabeth Gorecki ! ❤

  57. Stella cutie says:

    i went to a christian school and my favorite teacher ever adopted her youngest child. He had Down Syndrome. He is one of the cutest kids i have ever seen in my life!!!!! <333

  58. I guess that one way to make them feel special. For a day

  59. Jyoti Singh says:

    Gd morng Rajini…thanx fr th share…Genetics is rly intrstng…thanx again…

  60. Thanx for your information, it will help us greatly….

  61. Honestly I know one person who has it and she hasn’t yet stopped to amaze with her memory and attention to detail.

  62. i had to ask my cousin to understand it

  63. i did not read but just looked it looks like babies colorful socks

  64. Susheela Rao says:

    Nature balances in its own way.

  65. compliments to all my friends associated with and working for this noble cause …. support is much better than sympathy !!!!

  66. Susan LaDuke says:

    Thanks so much for the great informational share. For almost 5 years, I worked with an organization that provided group homes and job training for clients with syndromes and disorders such as this. They were almost always so bright, cheery and eager to learn as well as give back. They were truly some of most rewarding and memorable experiences.

    Tonight, on NBC Nightly News with Brian Williams, they highlighted a wonderful young man in their daily “feel good” segment. Tim Harris, is a 27 year old restauranteur, who graduated college in 2008 and has dreamed of having a place of his own since age 14. His family has helped and supported his dreams, helping to make it to fruition. Tim is also a very accomplished Special Olympian, having won more medals than the well known swimmer, and oh, by the way, Tim has Down Syndrome.

    He has a manager who helps him run the daily operations of Tim’s Place, but makes it his personal responsibility to greet every customer, and provide the well received hugs.

    So, on this day of recognition, I challenge each and every one to give someone, not necessarily a close friend or family member, a hug. It would really make Tim Harris’s day!

  67. Cody Cotten says:

    My brother Johnny has Hunter’s Syndrome. He’s 10 and he never says or does anything…I feel really bad for him.

  68. It’s the genetic code for people with down syndrome.  One of their chromosomes is basically broke in half. Resulting in down syndrome.

  69. Naidu Babu says:

    its called biology boss

  70. Divya Bedi says:

    u must be bio student

  71. very interesting now i can remember chromosomal abbreviation by date


  72. I have a special place in my heart for any one with a neurological disorder..  as a cousin of mine that has been my best friend since i was born has a disability that still has her loving her barbie dolls and teddy bears, and for the life of me i know it isnt down syndrome but i cannot remember the term for her condition, i just know she is one the sweetest and kindest people i have ever known..   And another cousin like twice removed or something..  she has down sydrome and is wheel chair bound because of other disabilities..  she strides through life just smiling and being so sweet to every one.. It would take a special kind of asshole to mess with any of these people..  and Down Syndrome Day should get more like a week or a month..  Honestly they deserve way better than just a day right?

  73. nelly dineo says:

    Wow its so incredibly when people tell something so interesting as this course I know it,I’m doing life science post more

  74. I had just read about this in book, now practically observed this image, also share some the symptoms related to this non-disjunction.  

  75. thanks 4 sharing too, nice post

  76. Aput Jackie says:

    though late response but soo grateful.

  77. Rajini Rao I read your posts and like them. But somewhere one of the comments brought back nagging question I have since school to the forefront-

    I am hoping that scientists like you and others can help.

    I assume that in olden days Latin was elite language so to give credence and force precise definitions, very uncommon words, terms and language was used in biology, chemistry and mathematics.

    This continues today. Unknowingly, you are depriving larger population from understanding and accepting science.

    So, can you make a pledge that when you do new research and discover new things, you would use most common language.

    Please go back to your posts and tell me how many times you spent words to just translate to make sense to seemingly intelligent people?

    I know many a times small words of uncommon nature carry compact meaning but that is not a very frequent cause of using unfamiliar words.

    If you think I am crossing my boundary, forget it! I just don’t think scientists should complain that people don’t accept science if they make it harder to understand by using purposefully inaccessible language.

    Every field is democratizing except these sciences……..

    Just my two cents!

  78. Rajini Rao says:

    You’re not crossing any lines at all and I appreciate your point of view! Specialized terms and technical jargon are in every field. I encountered them myself when I did my recent post on speciation in finches. I didn’t know what sympatric meant (sounded like they had the same father, haha). Some other terms were challenging too, since evolutionary biology is not my field at all. But all much was clear after I spent some time on the topic. I learned that sympatry and allopatry refer to populations that occur in the same geographical regions or separate ones 🙂 Rather nice terms, I think!  I guess it is not a big deal for me, because I can look at the prefixes sym and allo and figure out the basic meaning from their use in my own field.

    My bias is that specialized terms are very useful for conveying a precise meaning to specialists in the field. They are not that useful to the lay person, for whom the nuances may be less relevant to the main point. Would you still see that as elitist? What do you think? 

  79. Rajini Rao I agree that specialized terms are useful. I eluded to that by saying they are compact and precise.

    But that is not always the case. And at the end if it does not serve the purpose of accelerating discovery and rather delay the progress, it is just a waste.

    Assume that you are very much in the field, say in my case comp science, I still get very annoyed when a paper makes a point of using terms where there are simple plain English terms exist.

    The reason is, I better spend time developing next complex technology to solve problem that matter than spend time in Google to just start the process.

    You may not agree but even scientists (that includes my field of Comp science) use language to give credence to what they are saying.

    One more thing- I understand that language is just not a representation of ideas, but it is the birth place of ideas. There are tribes where if left and right terms are not part of the language, there is significant lack of understanding of the space coordinates.

    So, all power to the scientists when it is just important to introduce new concept.

    At the end, if we all intellectuals don’t make it a point to represent ideas in an easy consumable way, we all will be forgotten for what we stand for.

  80. Hi all,

    We are parents of a DS baby girl (Nagashree).  She’s now 9 years.  She had AV canal defect and was operated when she was 6 months old and the initial days were very tough (almost upto she reached 2 years).  She also had Pyogenic Menenzetis when she was 45 days old.  Though, as normal in DS babies, the milestones were delayed.  She started showing improvements from the age 2.5 – 3.  Now she goes to a school (pre primary).  We explored sending her to special school, but we feared she started imitating other MR kids.  I think she falls in borderline.  She has not developed writing skills, but identifies alphabet (english and kannada), numbers (1 -35) and this she was doing when she’s 5 years old.  Unfortunately, the schools in India do not adopt “Inclusive education”, if so, such babies would get the benefit a lot and I understand in the developed countries, “inclusive education” is much respected.  One interesting thing we notice in her is that she’s extra sensitive to what’s happening around her but never shows that she’s so.  There are occassions when her answers were just like a bullet, even before the question ends !!!  I am unable to crack the reason or thinking process she has.  It could be surely a subject of study…

    Presently, we are giving her “Ayurvedic Rejuvenation treatment” in Kerala by a doctor.  We do know that there are many therapies propagated, but that do not pass the test of logic sometimes, we feel there is surely some change in her.  We think, even if the improvement is 1%, thats worth it !.

    Coming to the discussion Ms Rajani Rao initiated, it nice to see the Karyotype pic.  One extra chromosome is cause of all the change (almost in all !!).  DS kids have special interest in Arts and Music – and that need to be explored …. I suppose great work surely comes out of them.

    We are open to share our views and details for the benefit of Nagashree and other such kids.

  81. Rajini Rao says:

    manjunathsamaga samaga , thank you for sharing the story of your daughter. All the best to her and to you as well, in raising her with love and care, as you are indeed doing! Have you checked out the Down Syndrome communities here on Google+? I did a search and found several that may be of help to you:

    Also, several parents of DS kids shared their experiences on this post. Perhaps you can reach out to them for mutual support and encouragement.

  82. Genetic disorders are the first treating problems in the world relating with mutation. therefore genetists have heavey problem.


  83. Guitar Dave says:

    Clearly shows that much work is needed and many mysteries still unlocked . Rajini how have you been ? You Always have brilliant subject matter and I thank you for that !

  84. Guitar Dave says:

    Hello Rajini how have you been ? I am reading about cellular mutations and how they affect downs or if they do at all .  From your vast knowledge of this are there mutations that are

    the cause of Downs or are there other factors and variables at play ? 

  85. Rajini Rao says:

    Hi there, Guitar Dave . Downs is caused by an extra chromosome, that increases the dose of several hundred normal genes (3 copies instead of 2 copies) rather than mutations in the genes themselves.

  86. Rajini Rao says:

    There’s a promising update on this story. Roger’s group has now shown that a single dose of an activator of the sonic hedgehog pathway not only restored the cerebellum of mice to normal size but also improved their learning and memory. This not ready for humans yet, but still a cause for much hope.

    Here is the pop sci story:

    Journal abstract:

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