Tyrosinemia Type I

HT1 is a rare, autosomal recessive, metabolic disorder caused by a deficiency in the enzyme fumarylacetoacetate hydrolase (FAH) that is encoded by the gene FAH. FAH is a key enzyme involved in catabolizing the amino acid tyrosine. FAH deficiency leads to the buildup of tyrosine and its metabolites in the blood and tissues such as liver and kidney. Patients usually suffer from severe liver disease. Treatment includes diet management to reduce tyrosine intake and nitisinone (NTBC) that prevents the formation of a toxic intermediate of tyrosine breakdown.