FAH and acute liver failure: Hereditary tyrosinemia type 1 (HT1) is caused by a deficiency in fumarylacetoacetate hydrolase (FAH) resulting in acute liver failure, neurologic crisis, HCC, and early death.1 HT1 is treated with the drug 2-(2-nitro-4-trifluoro-methylbenzyol)-1,3 cyclohexanedione (NTBC), also known as nitisinone, to inhibit the enzyme 4-hydroxyphenylpyruvate dioxygenase (Hpd), and block the buildup of downstream toxic metabolites.1 NTBC is combined with dietary restrictions of tyrosine and phenylalanine to lower tyrosine levels and prevent disease symptoms.