Citrullinemia is an inherited disorder that causes ammonia and other toxic substances to accumulate in the blood. Two forms of citrullinemia have been described; they have different signs and symptoms and are caused by mutations in different genes.
Type I citrullinemia, which is what Corrigan has, (also known as classic citrullinemia) usually becomes evident in the first few days of life. Affected infants typically appear normal at birth, but as ammonia builds up in the body they experience a progressive lack of energy (lethargy), poor feeding, vomiting, seizures, and loss of consciousness. These medical problems are life-threatening in many cases
Type I citrullinemia is the most common form of the disorder, affecting about 1 in 57,000 people worldwide. Type II citrullinemia is found primarily in the Japanese population, where it occurs in an estimated 1 in 100,000 to 230,000 individuals. Type II also has been reported in other populations, including people from East Asia and the Middle East.
Citrullinemia belongs to a class of genetic diseases called urea cycle disorders. The urea cycle is a sequence of chemical reactions that takes place in liver cells. These reactions process excess nitrogen that is generated when protein is used by the body. The excess nitrogen is used to make a compound called urea, which is excreted in urine.
Mutations in the ASS1 gene cause type I citrullinemia. This gene provides instructions for making an enzyme, argininosuccinate synthetase 1, that is responsible for one step of the urea cycle. Mutations in the ASS1 gene reduce the activity of the enzyme, which disrupts the urea cycle and prevents the body from processing nitrogen effectively. Excess nitrogen (in the form of ammonia) and other byproducts of the urea cycle accumulate in the bloodstream. Ammonia is particularly toxic to the nervous system, which helps explain the neurologic symptoms (such as lethargy, seizures, and ataxia) that are often seen in type I citrullinemia.
For more detailed information about Corrigan and his specifics please visit the following links: Rare Disease Day 2010
For information about Corrigan’s highest ammonia please go here
Are you considering a port to make blood draws easier? Here is our experience and a follow up post here so you can see how the scar has healed.
Are you considering a g-tube for your UCD child? you can check out some of our posts here, here and also here. It was not an easy decision but it was a great one, if you’d like to read about my concerns you can do so here, here and here.
For more information on all Urea Cycle Disorders please visit the National Urea Cycle Disorders Foundation at NUCDF.org
All posts, on Mooney=MC2, that include information about the medical care/treatment of Corrigan’s Citrullinemia are for personal documentation and in no way are to be taken as “medical advice.” All genetics teams have their own approaches to the management of Urea Cycle Disorders and just because our team does something a certain way does not mean that YOUR child’s team is doing it wrong. All management plans are customized to each child’s needs/disorder and Corrigan’s information is exclusive to his very specific needs and are overseen carefully by his team at Johns Hopkins Hospital.
If you have any questions about anything you read here, in regards to UCD’s, please feel free to take what you have read directly to your own team. Remember, I am just a mom, not a doctor…your child’s doctors are the best people to contact with specific medical questions…however, I would LOVE to talk to you about “everyday living” with Urea Cycle Disorders and would be happy to answer any questions regarding Corrigan…anytime at all.