World Down Syndrome Day 2024

Celebrating diversity and uniqueness this World Down Syndrome Day

Today (21 March) marks a special occasion in the global calendar, as families around the world celebrate diversity on World Down Syndrome Day (WDSD).

Designed as an opportunity to raise awareness and promote inclusion, 21 March was chosen to signify the uniqueness of the triplication of the 21st chromosome, which causes Down’s syndrome.

In the lead up to WDSD, Down Syndrome UK invited participants to get involved in 21 days of celebrations with various activities in schools across the country, and unique fundraising events.

People are also being encouraged to wear their most unique and fun socks for the day itself, to symbolise the uniqueness of every chromosome. Participants can also join the conversation on social media using #WorldDownSyndromeDay.

As a leading UK provider of DNA and genetic testing for members of the public, we know how important awareness and understanding is for people who have Down’s syndrome and their families.

In this blog, we explore what Down’s syndrome is, including the different types of Down’s syndrome, and how genetic screening for Down’s syndrome is performed during pregnancy. 

What is Down’s syndrome?

Down’s syndrome – also known as Down syndrome – is a chromosomal condition (trisomy) characterised by a person having a full or partial extra copy of chromosome 21.

It is sometimes referred to as Trisomy 21 and is one of the most common chromosomal conditions worldwide. It is estimated that there are around 47,000 people living in the UK who have Down’s syndrome.

People with Down’s syndrome present differently, depending on what type of Down’s syndrome they have. For most people, this usually includes mild to moderate intellectual disability, characteristic facial features, and may also include treatable medical conditions such as congenital heart defects, low muscle tone, and low thyroid levels.

However, many people who are born with Down’s syndrome lead healthy and active lives.

As our understanding of Down’s syndrome continues to grow, the clinical and social management of the condition improves, allowing many individuals to have jobs, relationships and to live independently.

Learn more about Down’s syndrome

What are the different types of Down’s syndrome?

There are three different types of Down’s syndrome:

  • Trisomy 21 – the most common form of Down’s syndrome, accounting for 95% of people with Down’s syndrome. This occurs when a person has a full, separate, extra copy of chromosome 21.
  • Mosaicism – which occurs when individuals have an extra copy of chromosome 21 in some, but not all cells in their body. Mosaic Down’s syndrome accounts for around 2% of people with Down’s syndrome.
  • Translocation – which occurs when individuals have an extra critical part of, or an extra whole copy of chromosome 21 that has become attached to another chromosome, rather than existing as its own extra chromosome. This accounts for the remaining 3% of people with Down’s syndrome.

Down’s syndrome does not usually run in families and is therefore not hereditary, with only 1% of Down’s syndrome cases having a hereditary component.

How is genetic screening for Down’s syndrome performed?

While many people with Down’s syndrome are valued in their communities, and lead healthy and active lives, Trisomy 21 pregnancies do, sadly, present an increased risk of miscarriage or stillbirth.

For this reason, many expectant parents choose to undergo screening for Down’s syndrome during pregnancy, so that the correct medical care can be provided for mother and baby throughout pregnancy and after the baby is born. 

Traditional screening offered by the NHS is known as the combined test and is typically performed between weeks 10 and 14 of pregnancy.

However, this screening is not offered to everyone, and will usually only be recommended in circumstances where the mother is considered to be at an increased risk of having a baby with one of the three most common chromosomal abnormalities (trisomies) – Down’s syndrome, Edward’s syndrome or Patau’s syndrome (due to her age, weight or other lifestyle factors).

The NHS combined test includes an ultrasound scan and a blood test to look at protein markers. The results of these tests are then used to assess the likelihood of the baby having one of these conditions, before more invasive diagnostic testing is offered.

However, as these screening tests are often carried out over several weeks throughout the first and/or second trimesters of pregnancy, some expectant parents may wish to pay for a private test, so that they can find out more quickly whether their pregnancy is high risk.

An AlphaBiolabs Non-invasive Prenatal Genetic Test is ideally suited for this purpose.

All the test requires is a blood sample from the mother, which can be collected from as early as 10 weeks into pregnancy and is available to anyone – not just expectant mothers who have been designated high risk.

Our non-invasive prenatal tests (NIPTs) – both Standard and Advanced – can detect 97.2%-100% of trisomies in single and twin pregnancies.

They can also be used to determine the sex of the baby while the mother is still pregnant, something which is not offered by the NHS.

Additionally, the results of our NIPTs are available in only 5 working days, meaning that you will receive your results much faster than if you were to follow the traditional NHS pathway.

For more information about this test, call our friendly and discreet Customer Services team on 0333 600 1300 or email

Non-invasive Prenatal Genetic Testing (NIPT)

Learn more or order your test online now.