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Test Code TYR DNA Tyrosinemia Type I, Mutation Analysis

Clinical System Name

Tyrosinemia, Mutation Analysis (6 mutations)


Tyrosinemia type I is an autosomal recessive disorder caused by a deficiency of the enzyme fumarylacetoacetate hydrolase. 


Analysis of the FAH gene for the following 6 common mutations: IVS12+5g>a, IVS6-1g>t, p.P261L, IVS7-6t>g, p.E357X., p.G337S.


This test may be indicated for individuals with: 

  • Elevated blood tyrosine and methionine
  • Elevated blood alpha-fetoprotein
  • Succinylacetone in urine

Sample Requirements

Specimen: Whole blood, cord blood

Container(s): Lavender/EDTA, Yellow/ACD A or B

Preferred Vol: 3 mL

Minimum Vol: 1 mL


Note: Heparin samples (Green tops) are unacceptable.


Specimen: Extracted DNA

Minimum: 10µg

Note: DNA concentration minimum 50 µg/mL; 260/280 ratio 1.70-2.00


Specimen: Cultured cells

Acceptable:  Fibroblasts

Container(s): T-25 flasks

Preferred Vol: 2 flasks

Processing Instructions

Reject due to: Heparin

Spin: No

Aliquot: No

Temp: Refrigerate

Storage location: Molecular Genetics box in CPA refrigerator #2


Off-site collection: Refrigerate blood samples until ready to ship.  Transport all sample types at room temperature via overnight shipping.


Specimen Type Temperature Time
Cultured cells Room temp 3 days
Whole blood, extracted DNA Room temp 3-5 days
Whole blood, extracted DNA Refrigerated 7 days
Extracted DNA Frozen ok


Note: Whole blood samples > 7days may be submitted to be assessed by our lab for acceptability for testing.


STAT Performed TAT
Contact lab Monday - Friday 2 weeks


Performing Laboratory

Seattle Children's Laboratory


Department:  Molecular Genetics Laboratory

Phone: 206-987-3872


Lab Client Services: 206-987-2617


Lab Genetic Counselor:

Reference Range

Interpretive report will be provided


Method: PCR + Sequencing


Limitations: This test is for targeted 6 mutation analysis only.

CPT Codes



Molecular Genetics

Clinical Utility

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.