Hereditary Tyrosinemia Type 1 in Turkey.

Hereditary tyrosinemia type 1 (HT1, OMIM 276700) is a rare autosomal recessively inherited inborn error of metabolism in the tyrosine catabolic pathway due to deficiency of the enzyme fumarylacetoacetate hydrolase. The clinical features of HT1 are widely heterogenous even within the same family members. Clinical features includes acute or chronic liver disease with increased risk of hepatocellular carcinoma, hypophosphatemic rickets due to renal tubular dysfunction, glomerulosclerosis, failure to thrive, neurological porphyria-like crisis, hypertrophic cardiomyopathy and hypoglycemia due to hyperinsulinism. Currently, the treatment in HT1 consists of two principles: inhibition of the formation of toxic metabolites by nitisinone [2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione; NTBC] and reduction of tyrosine levels by dietary treatment. In this chapter besides presenting the data for 42 patients that had been followed up by Pediatric Metabolic Diseases and Nutrition Unit, Cerrahpasa Medical Faculty, Istanbul University, we also evaluated the data abstracted from the previously published case studies in order to better understand the disease course and gain further insight in the current diagnosis and treatment for HT1 in Turkey.