What Is Down Syndrome?

Ages 3-5 Simple Explanation

You know how every person is made following a set of tiny instructions inside their body? These instructions tell your body how to grow — how tall to be, what color your eyes are, and everything about you! Most people have a certain number of these instructions, and they all match up in pairs.

Sometimes, a baby is born with one extra instruction. It's not something anyone did wrong — it just happens sometimes. When someone has that extra instruction, they have Down syndrome. It means their body and brain develop a little differently from most people.

Kids with Down syndrome might take a bit longer to learn things like talking, reading, or tying their shoes. But they do learn, and they keep learning their whole lives! They might look a little different too — that's because the extra instruction changes the way their face and body grow, just a little bit.

Kids with Down syndrome like to play, laugh, make friends, and do fun things, just like you! They have favorite toys, favorite foods, and favorite games. If you have a classmate with Down syndrome, being a good friend to them is one of the nicest things you can do. Everyone deserves a buddy!

Ages 6-8 More Detail

Inside every cell in your body, there are tiny things called chromosomes that carry the instructions for how your body is built. Most people have 46 chromosomes, arranged in 23 pairs. People with Down syndrome have 47 — they have one extra copy of chromosome number 21. This is why the medical name for Down syndrome is Trisomy 21, which means "three copies of 21."

This extra chromosome affects how the brain and body develop. Kids with Down syndrome usually learn things more slowly — like walking, talking, and reading. But with practice, support, and patience, they keep learning and growing their whole lives. Many kids with Down syndrome go to regular schools with some extra help.

People with Down syndrome often share some physical features. They might have a rounder face, eyes that tilt upward a bit, and smaller hands. But just like in any family, people with Down syndrome also look like their parents and siblings. No two people with Down syndrome look exactly alike or have the same abilities.

Down syndrome is not a disease and it's not contagious. It's just the way some people are born. Nobody did anything to cause it. It happens randomly when a baby is developing before birth, and it can happen to anyone.

Kids with Down syndrome have interests, talents, and personalities just like any other kid. Some love music, some love sports, some love art, and some love math. They experience happiness, sadness, excitement, and frustration — all the same feelings everyone has. Being a good friend to someone with Down syndrome is the same as being a good friend to anyone: be kind, be patient, include them, and get to know who they really are.

Ages 9-12 Full Explanation

Down syndrome is a condition caused by the presence of an extra copy of chromosome 21 in a person's cells. Normally, people have 23 pairs of chromosomes — 46 total. People with Down syndrome have 47 because they have three copies of chromosome 21 instead of the usual two. This is why it's medically called Trisomy 21. This extra chromosome is present from the very beginning of development and affects how the body and brain grow.

The extra chromosome causes certain physical characteristics and affects development. People with Down syndrome tend to have certain facial features — slightly upward-slanting eyes, a flatter facial profile, and smaller ears. They're also typically shorter than average and may have lower muscle tone. Most significantly, the extra chromosome affects brain development, which means people with Down syndrome usually have some degree of intellectual disability. Learning takes longer, but with the right support, people with Down syndrome can and do learn throughout their lives.

Down syndrome occurs randomly during cell division before or at the point of conception. It is not caused by anything either parent did or didn't do during pregnancy. It can happen in any family, regardless of background. The chance does increase somewhat with the mother's age, but babies with Down syndrome are born to parents of all ages. About 1 in every 700 babies in the United States is born with Down syndrome.

With better education, healthcare, and inclusion, the lives of people with Down syndrome have improved dramatically over the past few decades. Many attend regular schools with support, participate in sports and activities, learn to drive, hold jobs, and live independently or semi-independently. Average life expectancy has increased from 25 years in the 1980s to over 60 today, thanks to medical advances.

If you have a classmate with Down syndrome, the most helpful thing you can do is include them. They might need more time to process what you're saying, or they might communicate differently, but they understand far more than people sometimes assume. Be patient, be direct, and don't talk down to them. People with Down syndrome have real personalities, real opinions, real senses of humor, and they know when someone is being genuine versus just being polite.

Down syndrome is a significant part of someone's life, but it doesn't define everything about them. Just like you're more than your eye color or your height, a person with Down syndrome is more than their diagnosis. Getting to know them as an individual — their interests, their personality, their strengths — is always more meaningful than focusing on their differences.