What is Huntington’s Disease?

Huntington’s Disease is an illness that affects the brain and stops it sending messages to the body properly.  This means that our body and thoughts cannot work as well as they used to.  People get HD when they’re older – most people start to become unwell between the ages of 30 and 50.

What happens when someone has Huntington’s disease?

When someone has HD they may change and behave differently.  They may not be able to walk and talk as well as before, and they may be more forgetful.  Sometimes they may be more bad-tempered and get cross about little things. These changes take a long time and you might not notice them at first.

This is because of the way HD is changing their brain.  Our brain is very special and does lots of complicated things – it helps us to think, walk, play computer games, run, remember the way to school – everything we do in fact!  The brain is made up of millions of brain cells.

Why does Huntington’s disease change the way people move or behave?

When someone has HD, some of these brain cells become sick and start to die.  This stops some of the important information that’s whizzing around the brain from getting to where it’s supposed to go.  Imagine a relay race – each runner passes the baton on to the next runner, who then does their lap.  They pass the baton on to the next runner until they reach the finish line. If someone drops the baton, that team don't finish the race. In the brain the baton is the message that's being sent. This message gets passed through the brain from brain cell to brain cell until it gets delivered to the right part of the brain.

Example:  If you wanted to pick up a glass of juice, your eyes send a message to your brain about where the glass is, and then the brain sends a message to your arm and hand to move to the right place. This message is passed through the brain by your brain like in a relay race.

When someone has HD, the message is being passed along as usual but somewhere along the way, one of the brain cells drops the baton!  The message doesn’t get through properly and they drop the glass – smash!  This is why the person with HD can be clumsy sometimes and drop things or fall over.

With all this going on in the brain, HD stops people being able to do some of the things they could do before.

How long does Huntington’s Disease last?

People with HD can be unwell for a long time.  This is because the brain cells die slowly over many years.  They may live at home for a while and need lots of looking after.  After a while they may go to a special home to be looked after by nurses and other people.  You can still go and visit them in the home if you want to.

If you want to learn more about how the brain works, check out www.kidshealth.org

How do you get HD?

You might have more than one person in your family who has HD.  This is because HD runs in families – it is hereditary.  This means it can be passed from parents to their children. You might hear people talking about genes (say: jeenz).  Your body is made up of millions of cells and your genes are contained in each of these cells. Genes contain instructions for your body and decide things like what colour your hair is, how tall you are and the colour of your eyes. They are often called the building blocks of your body.  People might say that you look like other people in your family – this is because of your genes.  Genes are passed to you from your parents – that’s why you might have freckles like your dad, or brown eyes like your mum.  You have about 30,000 different genes in your body.

Sometimes genes don’t work properly and they cause people to become unwell.  HD is caused by a gene that doesn’t work properly.  This gene is what makes the brain cells die – nobody knows why.  Lots of scientists and doctors are trying to work out why – and hopefully find a cure for HD. We know a lot more about this gene now than we used to and are learning new things about how it works all the time.

If your parent has HD, there is a chance that you might get HD when you’re older.  BUT there’s the same chance that you won’t get HD at all, and hopefully the scientists will have found a way to make people with HD better by then.

If you want to learn more about how genes work, check out http://www.kidshealth.org or http://www.genecrc.org Kids only section.