Tyrosinemia type 1 (HT-1, OMIM 276700) is an inborn error of metabolism caused by a defect in the enzyme fumarylacetoacetate hydrolase (FAH) involved in the final step of tyrosine degradation with an estimated prevalence of 1 in 100,000 to 120,000 births worldwide, with higher prevalence in Quebec, Canada (~1 in 16,000 births). Here, FAH is linked to Tyrosinemia type 1.