Living With a Urea Cycle Disorder Tips for Sharing Your Medical Information Genetic Testing for UCDs

A urea cycle disorder (UCD) is caused by a defective gene in the body. Genes are part of our DNA, which determines the traits we have, such as eye color or hair color. Everybody has 2 copies of each gene: 1 from their mother and 1 from their father. When a gene isn't working correctly, it can cause health problems. Urea cycle disorders (UCDs) can be caused when one or both parents pass a copy of a defective UCD gene on to their child.

There Are 3 Ways You Can Get a UCD


One parent (typically the mother) passes on a defective gene via the X chromosome

· Men who inherit the defective gene will always have symptoms. Women who inherit the defective gene may or may not have symptoms. Men and women who have the defective gene are called "carriers" and can pass it on to their children. OTC deficiency is the only X-linked UCD.

Autosomal Recessive

Both parents pass on a copy of a defective gene via any chromosome other than the X or Y chromosomes

· People who inherit two copies of the gene that causes an autosomal recessive UCD will have UCD symptoms

Random Mutation

Also called "de novo," a mutation that happened for the first time when the cells were forming, creating a defective gene that caused a UCD

Basics of Genetic Testing

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A genetic test or "DNA test" allows doctors to find out if you have any defective genes that may cause a UCD. This test can also tell you your chances of passing a UCD on to your children. A genetic test can be ordered by a primary care doctor, a metabolic geneticist, or a genetic counselor.

During a genetic test, a doctor or nurse takes a sample of your DNA. This is usually done by drawing your blood or swabbing the inside of your mouth.

Then, your sample is sent to a lab where doctors look at your DNA to see if they find the defective gene that causes a UCD.

The results are sent back to your doctor, who will explain whether you have any defective genes related to UCD and what that means for your health.

You can find out if you have a UCD or carry the gene
that causes a UCD with genetic testing.

Things to Know Before Getting Genetic Testing

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How much it costs

The cost of a genetic test varies. Health insurance may cover some or all of the cost, but you and your family can also get a UCD genetic test at no cost to you.

How long it takes to get the results

It may take several weeks to several months for you to get the results of your genetic test. While you are waiting, it may help to meet with a doctor to discuss symptoms to look out for. If you use our UCD Genetic Testing Program, your results will typically be available within 10 to 21 days.

When you can get tested

You can decide to get a genetic test at any time in your life. Your genetic test results do not change over your lifetime.

How the test may affect your job or insurance

Depending on your circumstances, federal law may protect you from discrimination in your job or in getting health insurance based upon genetic test results.

The test is optional

The decision about whether to get a genetic test is a personal one. It may be helpful to talk to a genetic counselor before your genetic test to see if it is right for you.

Who to talk to if you have questions

Genetic counselors are a great source for information about genetic disorders and testing. They can help you understand the testing process and your risk of passing on a UCD.

Things to Talk to Your Doctor About Before Having a Test

It is important that you fully understand the following things before you give your permission for genetic testing:

  • How the test is done
  • benefits of the test
  • What the test will and will not be able to tell you
  • Possible results of the test
  • What the results mean for you and your family
  • Considerations about your privacy and personal information

If you have any questions at all or feel unsure about having a genetic test, talk to your doctor or another healthcare professional.

What are the Possible Results of a Genetic Test?

Positive, which means you carry the defective gene or genes that cause a UCD.

Negative, which means the test did not find any defective genes that cause a UCD.

Inconclusive, which means the test found something abnormal but doctors are unsure whether it is the defective gene that causes a UCD. This may require further testing.

A Guide to Genetic Testing Results

Genetic Testing Terms