Argininosuccinic aciduria

We each get two copies of most of our genes from our parents. One copy comes from our mother and the other copy comes from our father. In argininosuccinic aciduria, both parents must pass along a nonworking copy of the ASL gene. Because of this, argininosuccinic aciduria is inherited in what is called an autosomal recessive pattern. People who have one working and one nonworking copy of the ASL gene are called carriers. When both parents are carriers, for each individual pregnancy, there is a 25% chance that both parents will pass along a nonworking copy of the gene and the child will have the disorder. There is a 50% chance that one parent will pass on the gene change and the other will not, meaning the child will be a carrier for the disorder. Finally, there is a 25% chance that both parents will pass along a working copy of the gene and the child will not have the disorder and will not be a carrier.

If you are interested in finding out if you are a carrier for argininosuccinic aciduria, talk to your doctor about testing or contact a genetic counselor in your area. Genetic counselors can be found on the National Society of Genetic Counselors website in the United States, and in Canada at the Canadian Association of Genetic Counsellors website.

Argininosuccinic aciduria is caused by a change (variant) in the ASL gene. Not all changes in a gene necessarily cause disease. If a change is known to cause galactosemia, it is known as a pathogenic or disease-causing variant. However, sometimes gene changes are found and scientists are unsure what it means, either because it has not been found before or has only been found in a few people. This is known as a variant of unknown significance. If you have a variant of unknown significance in the ASL gene, talk to your doctor about further testing that may help find out whether the gene change is pathogenic or not. A genetic counselor may also be able to help you review your test results. Genetic counselors can be found on the National Society of Genetic Counselors website in the United States, and in Canada at the Canadian Association of Genetic Counsellors website.