--- title: World Down Syndrome Day: 5 Things to Know description: From how it happens to what it does canonical: https://time.com/3753355/world-down-syndrome-day/ author: Alice Park article:opinion: false article:content_tier: free article:published_time: 2015-03-21T17:05:59.000Z article:modified_time: 2026-05-11T05:04:57.011Z article:section: Health og:title: 5 Things to Know on World Down Syndrome Day og:description: From how it happens to what it does og:url: https://time.com/3753355/world-down-syndrome-day/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt1c5097bac9ca772c/6987849dcd1bba70ea6f5cba/world-down-syndrome-day.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 og:image:width: 1200 og:image:height: 675 og:image:alt: World Down Syndrome Day 2014 Celebrated in Indonesia og:type: article twitter:card: summary_large_image twitter:title: 5 Things to Know on World Down Syndrome Day twitter:description: From how it happens to what it does twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt1c5097bac9ca772c/6987849dcd1bba70ea6f5cba/world-down-syndrome-day.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  # 5 Things to Know on World Down Syndrome Day  by [Alice Park](https://time.com/author/alice-park/)  ## Alice Park Senior Correspondent Mar 21, 2015 5:05 PM UTC  A girl with Down syndrome takes part in planting a tree during World Down Syndrome Day on March 21, 2014 in Surabaya, Indonesia. A girl with Down syndrome takes part in planting a tree during World Down Syndrome Day on March 21, 2014 in Surabaya, Indonesia.Robertus Pudyanto—Getty Images  by [Alice Park](https://time.com/author/alice-park/)  ## Alice Park Senior Correspondent Mar 21, 2015 5:05 PM UTC Saturday is World Down Syndrome Day, a day recognized each year by the United Nations to raise awareness about the genetic disease. Here are five things you need to know about Down syndrome. 1\. Down syndrome is caused by an extra set of chromosome 21\. Every cell in the body has 23 pairs of chromosomes, one from each parent, but Down occurs when one parent contributes extra genetic material. Older mothers have a higher chance of having a Down baby. 2\. More than 400,000 people live with Down in the U.S. 3\. The most common symptoms of Down include cognitive delays, low muscle tone and a small stature. 4\. People with Down can lead full, independent lives. They are, however, at higher risk of developing heart, respiratory problems and certain cancers. 5\. People with Down are living much longer than in the past, thanks to treatments for their health issues. While the average life expectancy in 1983 was 25 years, today it is 60 years. ### You Asked: Your Top 10 Health Questions Answered  You Asked: Are Cleanses Healthy? Potions that claim to clear your body of toxins might sound alluring, but do they deliver? Illustration by Peter Oumanski for TIME  You Asked: Is Eating Dessert Really That Bad For Me? Bad news for sweet-eaters—except if you end your meals with this kind of treat. Illustration by Peter Oumanski for TIME  You Asked: What’s the Best Way to Whiten My Teeth? Yes, teeth whitening actually works—but here's why you have to dish out major bucks to see results. Illustration by Peter Oumanski for TIME  You Asked: Is Meditation Really Worth It? From easing stress to lowering heart disease risk, focusing your mind can do some amazing things for your body. Illustration by Peter Oumanski for TIME  You Asked: What’s the Healthiest Sweetener? Take a taste of the unsettled science of sweeteners. Illustration by Peter Oumanski for TIME  You Asked: Should I Go Paleo? The pros and cons of eating like a caveman. Illustration by Peter Oumanski for TIME  You Asked: Is Cracking Your Knuckles Bad? Here's what really happens to your joints when you snap, crackle and pop. Illustration by Peter Oumanski for TIME  You Asked: Is Running on a Treadmill as Good as Running Outside? You'll fool your body into thinking it's outside with this one small treadmill tweak. Illustration by Peter Oumanski for TIME  You Asked: Does Laughing Have Real Health Benefits? Here's proof that everybody could use a belly laugh. Illustration by Peter Oumanski for TIME  You Asked: What Is My Poo Telling Me? If you listen hard enough, you'll hear all kinds of health stories from #2. 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