Every year on the 21st of March we celebrate a condition which adds so much joy to our world. Down’s Syndrome! This year we don #lotsofsocks in an attempt to #leavenoonebehind.(1)

Most of us know the basics of what Down’s Syndrome is but here are some interesting facts about the condition.

It’s a special rarity

It is estimated that one every 1000 live births in developed countries have Downs Syndrome. However, in developing countries such as South Africa, the prevalence is about one in 650 live births. (2)

It’s just an extra chromosome (3-5)

Humans generally have 23 pairs of chromosomes which create our genetic make-up. In normal development of a cell, one cell (egg or sperm) divides into two and the chromosomal pairs split so that one of each chromosome can go into each cell. Down’s Syndrome, however, is caused by an error in the division of cells (non-disjunction) which leads to an extra chromosome 21. This happens when both chromosomes of the same pair enter a single cell, leading to an extra copy of chromosome 21. The three-chromosome presentation is also be called trisomy 21.

But did you know that there are other types of Downs syndrome? Most of us know about complete trisomy 21 as explained above. But there are also two other trisomies 21 presentations.

Complete trisomy 21

Occurs when, before conception, either the egg or sperm cell has a complete pair of chromosome 21. Once they merge to form the zygote (which will become the embryo), the cell will have an extra chromosome 21 and this trisomy will be present in every cell of the developing child as the zygote divides to form the embryo. Most cases result from complete trisomy.

Mosaic trisomy 21

This type occurs in less than 5% of cases. Mosaic trisomy 21 occurs when the error in cell division takes place early in development but after a normal egg and sperm unite. This leads to some cells having the trisomy 21, where others will present as ‘normal’ cells with only paired chromosomes. Another possibility is that the cells had trisomy 21, but during division, some of the cells lost the additional chromosome.

Translocation trisomy 21

Very few cases are caused by this type of chromosomal change. In this situation only a fragment of an extra chromosome 21 is present. The extra part of the chromosome becomes fixed to another chromosome and moves along in cell division as.

No reason to not be happy(6-9)

In 1983, the average life expectancy of a person with Down syndrome was 25-years-old but with improved medical understanding and care, the average is now 60-years-old. Additionally, a recent (2011) study indicates that 99% of people with Downs Syndrome are happy with their lives.

In studies by the same authors, it was found that 97% of parents were proud of their child with DS and 79% felt that they had a more positive outlook on life because of their child. With regards to siblings, 94% of older siblings expressed pride in their younger sibling with DS. Additionally, 88% felt that because of their sibling with DS, they had become better people. The vast majority of brothers and sisters described their relationship with their sibling with DS as positive and enhancing.

Happiness, bear hugs and adorable smiles; what could be better?

So, what is World Down Syndrome Day about? (1, 2)

Leaving nobody behind. Access for all. Acceptance for everyone. Joy and happiness, hugs and smiles, bright colours and #lotsofsocks! The day is celebrated on the 21st day of the thirds month to represent the trisomy of chromosome 21.

We encourage you to wear your mismatched, brightest, happiest socks this Thursday. Don’t be shy. Wear them to work, to school, to university, on your feet, on your hands or on your head. Have fun and remember it’s all about awareness so make sure you get loads of photos and post them on Facebook, Twitter and Instagram using the hashtags #LotsOfSocks, #WorldDownSyndromeDay and #WDSD19.


You may have seen this Instagram post (yes it went viral) but have a read of this ‘review’ written by Jessica Young Egan, a mommy of a little girl with Down Syndrome:

“When I placed my order I said, ‘Regular amount of chromosomes, please!’ That’s what everyone else got and what I wanted too. They called me shortly after my order was in production and said ‘Great news, we went ahead and upgraded you to extra chromosomes for free! You’ll receive the extra chromosomes with your completed order in 9 months.’

 What?! I was mad!

“All the other orders I had seen displayed via perfect Instagram posts did NOT have extra chromosomes. Well, I decided that receiving my order with extra chromosomes was better than not receiving an order at all, so I settled in to wait for this surprise upgrade to arrive. I have now had my order for two months and am writing this review to let others know the upgrade to extra chromosomes is amazing!! If offered, definitely take it! I posted some photos below of the finished product and you can see the extra chromosome is so worth it – it is extra cute, extra special, and extraordinary! So much extra joy. Would purchase again for sure.”



  1. World Down syndrome day. 2019.
  2. (GARD) GaRDIC. Down Syndrome 2012.
  3. Dr L Leshin M, FAAP Mosaic Down Syndrome [14/03/2019]. Available from: https://www.imdsa.org/mosaic-down-syndrome.
  4. Foundation GDS. FAQ and Facts about Down Syndrome 2014 [
  5. Patterson D. Genetic mechanisms involved in the phenotype of Down syndrome. Ment Retard Dev Disabil Res Rev. 2007;13(3):199-206.
  6. Brian G Skotko SPL, Richard Goldstein. Having a son or daughter with Down syndrome: Perspectives from mothers and fathers. American Journal of Medical Genetics. 2011;v155 n10 (October 2011)(Part A ):2335-47.
  7. Brian G Skotko SPL, Richard Goldstein. Having a brother or sister with Down syndrome: Perspectives from siblings. American Journal of Medical Genetics:. 2011;Part A v155 (n10 (October 2011)):2348-59.
  8. Brian G Skotko SPL, Richard Goldstein. Self-perceptions from people with Down syndrome. American Journal of Medical Genetics 2011; Part A v155 (n10 (October 2011)):2360-9.
  9. Saunders DP. 99% of People With Down Syndrome Happy With Their Lives London, England 2013 [Available from www.lifenews.com/2013/10/18/.