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Diagnostic Services

Genetics Lab


Tyrosinemia Type I Known Mutation Analysis

Tyrosinemia type I is an autosomal recessive disorder caused by a deficiency of the enzyme fumarylacetoacetate hydrolase. The disease manifests primarily as liver disease, with hepatic cirrhosis and accompanying renal tubule damage as a result of the build up of succinylacetone. Biochemically, the hallmarks of the disease are elevated blood tyrosine and methionine, elevated blood alpha-fetoprotein, and succinylacetone in the urine. The diagnosis is confirmed by the presence of succinylacetone in urine. The disease is common in the French Canadian population, with a carrier frequency of 1/25 in people from the Saguenay-Lac St John region of Quebec. The overall carrier frequency in Quebec is 1/66.

Test Name: Tyrosinemia Known Mutation Analysis
Test Code:
Test Description:
Analysis of the FAH gene for known familial mutations
This test is used for carrier testing at-risk relatives and prenatal testing for confirmed carriers. Mutations must be known.
Related Tests: Tyrosinemia Type I (6 mutations)  
This test is used to provide additional information regarding diagnosed patients, provide carrier testing for at-risk family members or general population carrier screening.

NTBC (Orfadin) Level  
For monitoring therapeutic drug levels in patients being treated with Orfadin (nitisinone).

Succinylacetone Screening, Urine  
This is a semi-quantitative assay for succinylacetone as part of urine organic acids. This screen is used for patients suspected of having tyrosinemia type I.

Succinylacetone Quantitation, Urine  
This stable isotope assay is used for monitoring known patients with tyrosinemia type I.

Maternal Cell Contamination - DNA  
Maternal DNA is compared to fetal DNA to evaluate whether maternal cell contamination of the fetal sample has occurred.

Clinical Links: Tyrosinemia Type I GeneReview
University of Washington Tyrosinemia Webpage
Performed weekly
Turnaround Time:
2 weeks
PCR and sequencing
Reference Range:
Interpretive report provided
Consent Form:
Sample Requirements: Type
Whole blood: 1-3 mL in EDTA (purple top) or ACD (yellow top).
DNA: 5ug extracted DNA
Prenatal Samples:2 T-25 flasks cultured cells (CVS or amnio)

Do not spin. Keep at room temperature

Room temperature via overnight shipping. Blood samples MUST be processed within 3 days of collection.
Ship cultured cells in appropriate media.
Samples Received:
Mon – Fri 8:00 am – 5:00 pm PST
Special Considerations:
For prenatal testing, maternal cell contamination testing is required (ordered separately).
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions
CPT Code:
Please e-mail Lab Client Services ( or call at 206-987-2617 with any billing questions