Tyrosinemia Type 1 DNA Test

Are you a genetic carrier for tyrosinemia type I? Find out with this DNA Test.

  • Detects four FAH variants which cause tyrosinemia type I
  • Characterized by elevated levels of the amino acid tyrosine
  • Carrier screening test intended for couples who are planning to become pregnant
  • 100% private and confidential online results

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Detailed Description

Tyrosinemia is an inherited metabolic disorder characterized by elevated levels of the amino acid tyrosine, a basic building block of many proteins. Tyrosinemia can be classified into three types based on symptoms and the underlying genetic cause.

Tyrosinemia type I is most common in people of French Canadian, Finnish, Ashkenazi Jewish, Norwegian, and Turkish descent. It is caused by genetic variation in the FAH gene, which reduces the function of the fumarylacetoacetate hydrolase enzyme. This enzyme is involved in the last step of the pathway that breaks down tyrosine. A cellular buildup of tyrosine and tyrosine byproducts occurs in affected individuals, which can cause cell damage in the liver, kidneys, and nervous system.

Take this test to find out if you are a genetic carrier of an FAH variant and are at risk of passing it to your children.

The Genetics

Tyrosinemia type I is caused by genetic variation in the FAH gene. This gene gives instructions to make the fumarylacetoacetate hydrolase enzyme, which is involved in the last step of the pathway that breaks down tyrosine. Affected people produce an enzyme with reduced function, leading to a buildup of tyrosine and tyrosine byproducts in cells.

Tyrosinemia type I is inherited in an autosomal recessive pattern, which means two defective copies of the FAH gene must be inherited in order for symptoms to appear.

Variants Tested

This test detects four genetic variants in the FAH gene that occur in >99% of Ashkenazi Jewish carriers, approximately 90% of French Canadian carriers and 86% of Finnish carriers of tyrosinemia type I.

  • rs80338899
  • rs80338898
  • rs80338901
  • rs80338895

Understanding your carrier status for these variants will help you understand the risk of passing a variant to your children.

Signs and Symptoms
  • High level of tyrosine in blood
  • Failure to thrive
  • Liver problems (hepatomegaly, cirrhosis, liver failure)
  • Kidney problems (tubular dysfunctions, glomerusclerosis)
  • Neurologic crises (mental status change, abdominal pain, respiratory failure requiring mechanical ventilation)
  • Higher liver cancer risk (especially in those who are diagnosed later, and don’t receive Nitisinone treatment as newborns)
  • Impaired blood clotting (coagulation)
  • Rickets

How It Works

Step 1: Sign up for a free DNA Access account.
Step 2: Upload your DNA markers to DNA Access.
Step 3: Log in to your account to access your results when they are ready.