A Urea Cycle Disorder is a rare genetic condition where the Urea Cycle within the liver does not function normally. When the body digests protein it is broken down into small molecules known as amino acids. These travel through the blood stream and are transported to the cells. Excess amounts of these amino acids are converted into a toxic substance known as ammonia. Ammonia is then converted to a non-toxic chemical called urea which we excrete in urine. This process all takes place via the Urea Cycle. A person with a Urea Cycle Disorder cannot excrete ammonia via the Urea Cycle which can cause a build-up of toxic Ammonia in the body.

A urea cycle disorder is an inherited genetic disease, this means it is something you are born with. You inherit different genes from your mother and father. Some carry the information that determines the colour of your hair or eyes, whilst other genes have information which may be related to a genetic disease. UCDs can be passed down in families when a parent passes the defective gene to the child. UCDs can also be the result of a spontaneous genetic mutation, which means it happens regardless of the parents’ genes.

No, it is not contagious. The disease did not come about because of a virus or bacteria; it arose due to an error in the genes.

You are you; you are not your disease. Everyone is different. Someone with a UCD just has a medical condition that has to be treated and managed.

It may be tough at times to keep taking your UCD medicines, but not taking them may lead to a dangerous build-up of ammonia in your blood (hyperammonaemia). Hyperammonaemia can be harmful to your body. 

Hyperammonaemia means high ammonia levels and is a build-up of Ammonia in the blood. Hyperammonaemia can be very harmful to the body, so it is important that ammonia levels are kept within a safe range. Hyperammonaemia can lead to something called a Decompensation (also called Hyperammonaemic crisis). A decompensation can occur when ammonia levels reach such high levels that they become extremely toxic. A decompensation requires emergency medical attention.

UCD’s affect everyone differently and at different times. Someone whose UCD is being well managed with diet and medicine may have long periods of time without hyperammonaemia or a hyperammonaemic crisis. Triggers such as illness, exam stress or eating the wrong foods can all lead to the build-up of Ammonia in the blood over time. Eating the wrong foods might not make you feel immediately sick, but can cause harm if ammonia levels continue to rise.

Symptoms of a urea cycle disorder may appear at any time and can vary from person to person. Symptoms can be vague, but even if your ammonia levels only go up by a small amount, you might start to feel poorly and experience symptoms.

Common symptoms of high ammonia include:

  • Feeling very tired
  • Finding it difficult to think clearly
  • Feeling wobbly/dizzy
  • Headaches
  • Shaky hands
  • Body parts moving or twitching when you don’t want them to
  • Finding it hard to speak
  • Not feeling hungry or not wanting to eat protein (such as meat, eggs and dairy)
  • Tummy ache
  • Feeling sick or vomiting
  • Feeling very angry or upset

If you eat too much protein, your ammonia levels will increase – and this can be harmful. Your special diet helps to control the amount of harmful substances in the body and make you feel better. If you have difficulties with your low-protein diet, speak to your doctor.

A UCD won’t disappear with time so you will likely need to stay on a special diet and take medicines for the rest of your life.

The levels of ammonia in your body will build up and you may feel very ill indeed! You may need to come into hospital for special medicines. So, it is very important that you continue to take your medication and stick to your diet!

UCD is a genetic disease, which means it will stay for the rest of your life. The medicines you are taking and your diet will help you to manage it. You may experience that your body produces more ammonia than usual at some occasions, which can be caused by infections (a cold, influenza). Stressful situations can also trigger it. This lasts for a short time and you may feel sick.

It is probably best to let people in your surroundings know about your condition. Then they will understand why you are on a special diet and medicines.