Tyrosinemia type 1: clinical and biochemical analysis of cases with poor treatment outcome

ABSTRACT

Tyrosinemia Type I [TT1] is a metabolic disorder with impaired activity of fumarylacetoacetate hydrolase enzyme. The causes of death are liver failure, pseudo porphyric crisis and hepatocarcinoma. The treatment is based on diet restriction, liver transplantation and the NTBC. Aim: To review the clinical presentation, biochemical analysis and expose the causes of failure of treatment in 3 patients with TT1. By studying the clinical and biochemical data of 3 dead patients with TT1 [part of the total 15 patients with the same diagnosis], during [October 2001 to October 2009].The diagnosis was established by high tyrosin in the blood and succinylacetone in the urine. Monitoring was based on the combination of liver imaging, and alpha feto protein as tumor marker. Two patients were treated by NTBC and diet restriction [patients 1 and 2] while the 3rd patient was treated by diet restriction only. Overall survival rate was 80% [85.7% in those treated by NTBC]. The age at onset was respectively 8, 5 and 1.5 months .The age at diagnosis was 40, 6 and 6 months. All three patients were presented with severe liver failure. [PT ranged from 21% to 24%], patient 1 was treated with NTBC for 4 months and died after 2 months of stopping NTBC. The second patient did not respond to NTBC and died after 5 months of treatment. The third patient died after 2 months of treatment. A. Poor prognosis in patient 1 and 2 could be explained by [1] The dose was less than 2mg/kg/d [2] Late diagnosis in patient 1. [3] Difficulty of management and monitoring. B. Poor prognosis in patient 3 was on diet restriction as in the literature. C. Slow decrease of alpha feto protein can explain the possibility of hepatocarcinoma in patient 1 and 2 but the duration of the treatment was short to conclude, the increase in patient 3 is well known as a part of hepatocarcinoma mechanism. [1] Early diagnosis and starting NTBC with diet restriction give good prognosis. [2] Starting neonatal metabolic screening